Move job not found response to earlier, outdent
Move job not found response to earlier, outdent

If there is no `job` found, bail earlier in the method. This favors the
"fail early" approach, removing one conditional branch from the method,
as we assume that if `job` is not nil, we must have a job object to work
with.

tuxmea/lita-jenkins,miketheman/lita-jenkins,daniely/lita-jenkins