This is a bugfix over __init__.py that was inititalliy changed at https://github.com/reviewboard/reviewboard/commit/915452d483a812ee34006741a6f5c23a4d03a5b1

The current initialization is overzealous and conflicts with the installation call from extensionbrowser's easy_install usage (with the current initialization, an easy_install call would nuke all entries in the easy_install.pth file and overwrite previous entries).