speculative fix for python problem introduced in 2.7.4

Per discussion on IRC with @mistydemeo and soulshake and subsequent investigation.

Soulshake noticed a problem (which I reproduced) seemingly introduced by the python 2.7.3->2.7.4 upgrade, whereby running `/usr/bin/vim` and executing `:python import sys` produces a long traceback about MAXREPEAT and crashes vim (and screws up the terminal for good measure, but maybe that's just me).

We found this Debian bug (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=704084) where they claim to have fixed the problem. However, it persists. soulshake and I fixed it locally by commenting out a few things, so I put that into the formula. But that might not be the right place for this fix (maybe we should report it somewhere upstream, etc).

Ping: @samueljohn