ovs-brcompatd: Don't delete bridge twice.

ovs-brcompatd: Don't delete bridge twice.

Somehow I totally goofed when I wrote commit dcdf169e "ovs-brcompatd:
Delete Bridge record when deleting a bridge."  In fact, del_bridge()
already deleted the Bridge record, and I missed that, and so I added a
*second* call to ovsrec_bridge_delete(br).  Obviously that's bad.

This commit removes the first call to delete the bridge.  It is a slight
improvement over simply reverting the buggy commit in that it doesn't
refer to 'br' (just as a pointer equality comparison) after deleting it.

Bug #2448.