Tidy up Sheriffbot's Sheriffs command's unit tests
https://bugs.webkit.org/show_bug.cgi?id=108262

Patch by Alan Cutter <alancutter@chromium.org> on 2013-01-29
Reviewed by Eric Seidel.

Added the use of MockWeb instead of the filesystem to test the sheriffs command.

* Scripts/webkitpy/tool/bot/irc_command.py:
(Sheriffs._retrieve_webkit_sheriffs):
(Sheriffs.execute):
* Scripts/webkitpy/tool/bot/irc_command_unittest.py:
(IRCCommandTest.test_sheriffs):
* Scripts/webkitpy/tool/bot/testdata/webkit_sheriff_0.js: Removed.
* Scripts/webkitpy/tool/bot/testdata/webkit_sheriff_1.js: Removed.
* Scripts/webkitpy/tool/bot/testdata/webkit_sheriff_2.js: Removed.
* Scripts/webkitpy/tool/bot/testdata/webkit_sheriff_malformed.js: Removed.
* Scripts/webkitpy/tool/bot/testdata/webkit_sheriff_zero.js: Removed.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141206 268f45cc-cd09-0410-ab3c-d52691b4dbfc