Drop OpenSSL 0.9.8 (#2978)

* Drop OpenSSL 0.9.8

* Drop this test, it's not relevant any longer

* unused import

* Remove CRYPTOGRAPHY_ALLOW_OPENSSL_098=1 from our tox

* removed unused code for Cryptography_HAS_PKEY_CTX

* return unused code for _AESCTRCipherContext

* syntax :-(

* remove some unused tests and skips

* remove unused code for Cryptography_HAS_PBKDF2_HMAC

* Revert "return unused code for _AESCTRCipherContext"

This reverts commit 7d149729205aa4c9735eb322414b167a75b302df.

* Remove unused RSA code

* Remove unused test code for conditional bindings

* Remove unused dsa code

* unused import

* Remove unused x509 extension code

* Remove unused EC code

* Attempt to remove unused DER key loading code

* document this

* grammar

* Added back this paragraph

* Update docs

4 files changed, 11 insertions, 16 deletions

diff --git a/docs/faq.rst b/docs/faq.rst
index 76dc4f3d..2ddc5db8 100644
--- a/docs/faq.rst
+++ b/docs/faq.rst
@@ -40,8 +40,8 @@ If you have no other libraries using OpenSSL in your process, or they do not
 appear to be at fault, it's possible that this is a bug in ``cryptography``.
 Please file an `issue`_ with instructions on how to reproduce it.
 
-Importing cryptography causes a ``RuntimeError`` about OpenSSL 0.9.8
---------------------------------------------------------------------
+Installing cryptography with OpenSSL 0.9.8 fails
+------------------------------------------------
 
 The OpenSSL project has dropped support for the 0.9.8 release series. Since it
 is no longer receiving security patches from upstream, ``cryptography`` is also
@@ -49,9 +49,9 @@ dropping support for it. To fix this issue you should upgrade to a newer
 version of OpenSSL (1.0.1 or later). This may require you to upgrade to a newer
 operating system.
 
-For the 1.4 release, you can set the ``CRYPTOGRAPHY_ALLOW_OPENSSL_098``
-environment variable. Please note that this is *temporary* and will be removed
-in ``cryptography`` 1.5.
+In ``cryptography`` 1.4, you can set the ``CRYPTOGRAPHY_ALLOW_OPENSSL_098``
+environment variable. Please note that this is *temporary* and is removed in
+``cryptography`` 1.5.
 
 .. _`NaCl`: https://nacl.cr.yp.to/
 .. _`PyNaCl`: https://pynacl.readthedocs.io
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index f488a8bc..8bc7dac5 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -3,9 +3,8 @@
 OpenSSL backend
 ===============
 
-The `OpenSSL`_ C library. Cryptography supports version ``0.9.8e`` (present in
-Red Hat Enterprise Linux 5) and greater. Earlier versions may work but are
-**not tested or supported**.
+The `OpenSSL`_ C library. Cryptography supports OpenSSL version ``1.0.0`` and
+greater.
 
 .. data:: cryptography.hazmat.backends.openssl.backend
 
diff --git a/docs/hazmat/bindings/openssl.rst b/docs/hazmat/bindings/openssl.rst
index 8935093f..8aef4883 100644
--- a/docs/hazmat/bindings/openssl.rst
+++ b/docs/hazmat/bindings/openssl.rst
@@ -6,8 +6,7 @@ OpenSSL binding
 .. currentmodule:: cryptography.hazmat.bindings.openssl.binding
 
 These are `CFFI`_ bindings to the `OpenSSL`_ C library. Cryptography supports
-version ``0.9.8e`` (present in Red Hat Enterprise Linux 5) and greater. Earlier
-versions may work but are **not tested or supported**.
+OpenSSL version ``1.0.0`` and greater.
 
 .. class:: cryptography.hazmat.bindings.openssl.binding.Binding()
 
diff --git a/docs/installation.rst b/docs/installation.rst
index cb876b8f..a2455c24 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -13,7 +13,7 @@ Supported platforms
 Currently we test ``cryptography`` on Python 2.6, 2.7, 3.3, 3.4, 3.5, and PyPy
 2.6+ on these operating systems.
 
-* x86-64 CentOS 7.x, 6.4 and CentOS 5.x
+* x86-64 CentOS 7.x, 6.4
 * x86-64 FreeBSD 10
 * OS X 10.11 El Capitan, 10.10 Yosemite, 10.9 Mavericks, 10.8 Mountain Lion,
   and 10.7 Lion
@@ -28,8 +28,6 @@ Currently we test ``cryptography`` on Python 2.6, 2.7, 3.3, 3.4, 3.5, and PyPy
 We test compiling with ``clang`` as well as ``gcc`` and use the following
 OpenSSL releases:
 
-* ``OpenSSL 0.9.8e-fips-rhel5`` (``RHEL/CentOS 5``)
-* ``OpenSSL 0.9.8k``
 * ``OpenSSL 1.0.0-fips`` (``RHEL/CentOS 6.4``)
 * ``OpenSSL 1.0.1``
 * ``OpenSSL 1.0.1e-fips`` (``RHEL/CentOS 7``)
@@ -38,9 +36,8 @@ OpenSSL releases:
 * ``OpenSSL 1.0.2-latest``
 
 .. warning::
-    OpenSSL versions 0.9.8 and 1.0.0 are no longer supported by the OpenSSL
-    project. Cryptography 1.4 has dropped support for OpenSSL 0.9.8, see the
-    :doc:`FAQ </faq>` for more details.
+    OpenSSL 1.0.0 is no longer supported by the OpenSSL project. Cryptography
+    will drop support for it in a future release.
 
 On Windows
 ----------