Force types on 'log-size' and 'log-count' arguments for "create-master" command

Previously these arguments were treated as string and passed as strings to
twisted.python.logfile.LogFile.fromFullPath() in buildbot.tac:

rotateLength = '10000000'
maxRotatedFiles = '10'


That led to invalid behaviour of Twisted logger - logs doesn't rotated at all.

Also removed unused "import re" from `master/buildbot/scripts/runner.py` - I doesn't touched this file and it's strange that pyflake started to complain about this issue only now.