don't use deprecated BaseException.message

This fixes following deprecation warning:

buildslave/scripts/create_slave.py:215: DeprecationWarning:
        BaseException.message has been deprecated as of Python 2.6
console: remove limit of 25 changesets requested from db.
console: remove doubling of builds requested if devName set.

When the revs parameter is large doubling the number of builds would
significantly increase loading time. Setting the devName does not increase
or decrease the number of changesets loaded from db, so there is not
much help in only increasing the number of builds loaded.
Merge branch 'console_rev_count' of git://github.com/thedylman/buildbot
Merge branch 'fix-deprecated-warn' of git://github.com/elmirjagudin/buildbot