help: remove references to "Python 2.6 or later"

We require Python 2.6. So there is no value to these docs.

mercurial/help/config.txt

@@ -986,9 +986,6 b' For example::'
     hg.intevation.de = fc:e2:8d:d9:51:cd:cb:c1:4d:18:6b:b7:44:8d:49:72:57:e6:cd:33
     hg.intevation.org = fc:e2:8d:d9:51:cd:cb:c1:4d:18:6b:b7:44:8d:49:72:57:e6:cd:33
 
-This feature is only supported when using Python 2.6 or later.
-
-
 ``http_proxy``
 --------------
 
@@ -1849,11 +1846,6 b' The full set of options is:'
     client, then it will verify the identity of remote HTTPS servers
     with these certificates.
 
-    This feature is only supported when using Python 2.6 or later. If you wish
-    to use it with earlier versions of Python, install the backported
-    version of the ssl library that is available from
-    ``http://pypi.python.org``.
-
     To disable SSL verification temporarily, specify ``--insecure`` from
     command line.