update cacerts from mozilla.org

Used mk-ca-bundle.pl locally to generate a recent cacerts.txt file that
fixes https certificate validation for OSX 10.8x. These certs were built
with:

$ perl mk-ca-bundle.pl -w 64 boto/cacerts/cacerts.txt

fixes boto/boto#1535
closes jtriley/StarCluster#267
Merge branch 'jtriley-update-cacerts' into develop

Closes # 1578.

* jtriley-update-cacerts:
  update cacerts from mozilla.org