Fix for bug 84596: Syncshadowdb wasn't using the db_user and db_pass from localconfig, which meant that it previously wouldn't run unless it was running under a user that had access to the bugs and shadowbugs dbs and didn't have a password.  It now looks for db_user and db_pass and specifies them on the command line to mysqldump and mysql if they're in use.
r= tara