Remove the branches table from the database

This table is actually unnecessary, and causes some confusion when
setting up a new Gerrit installation, or a new project.

Bug: issue 299
Change-Id: If19f3474a7b5e3adba3b09c470a01927fe46cb58
Signed-off-by: Shawn O. Pearce <sop@google.com>
10 files changed