[server/session] make commit/rollback obey ensure_cnx_set Inside the ensure_cnx_set context manager, commit and rollback aren't allowed to dispose of the cnxset.

[repo] fix deprecation messages for stats and gc_stats

[cwconfig] use "foo not in bar" instead of "not foo in bar"

[debian] Add Breaks on a few cubes that need changes for 3.19 - mercurial_server is affected by composite deletion changes - forgotpwd relied on session data to be forwarded to notification view - registration hooks into the authentication stack