Merge failing-tls-tests-7370

Author: exarkun (sponsored by Hybrid Logic, Ltd.)
Reviewer: glyph
Fixes: #7370

Generate a new and larger RSA key (and associated self-signed certificate)
for use by a number of the TLS unit tests.  This causes them to pass when
the test suite is run using pyOpenSSL 0.14 or newer and an EC-supporting
version of OpenSSL.  The tests previously failed because the newer EC-using
TLS configuration introduced in r41888 requires this larger RSA key (the
old key was 512 bits, an unreasonably small size) to successfully complete
a handshake.

Note this change is unit tested (it is really only a fix to the unit tests)
but there is presently no continuous integration coverage for this case
because the continuous integration system is not configured to run the tests
against pyOpenSSL 0.14 in any cases.


git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/trunk@43114 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb