controller: Fix race in TestRunJobAttached
controller: Fix race in TestRunJobAttached

This test was racing with the one-sided close detection in the
controller handler.

Signed-off-by: Jonathan Rudenberg <3692bfa45759a67d83aedf0045f6cb635a966abf@titanous.com>

flynn/flynn,philiplb/flynn,philiplb/flynn,lmars/flynn,philiplb/flynn,philiplb/flynn,lmars/flynn,lmars/flynn,lmars/flynn,flynn/flynn,flynn/flynn,flynn/flynn,flynn/flynn,lmars/flynn,philiplb/flynn