don't use a method that expects a result for a function that doesn't return one
don't use a method that expects a result for a function that doesn't return one

thereby avoiding a warning about not knowing how to handle the type of pg_advisory_xact_lock

Change-Id: I4bdc6c04c29b7fc6e88060e9888d2029d56bf362
Reviewed-on: https://gerrit.instructure.com/c/inst-jobs/+/236301
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Jacob Burroughs <8ecea6e385af5cf9f53123f5ca17fb5fd6a6d4b2@instructure.com>

instructure/inst-jobs,instructure/inst-jobs,instructure/canvas-jobs,instructure/inst-jobs,instructure/canvas-jobs,instructure/canvas-jobs,instructure/inst-jobs,instructure/canvas-jobs