Zuul: remove file matcher for devstack job
Zuul: remove file matcher for devstack job

The file matcher was from the early versions of this when we were
running both v2 and v3.  We should always run the new devstack
job on all changes to devstack now that v3 is in production and we
plan on building jobs off of this one.

Change-Id: I7dd336b0059043f6653bdfdcba0ee5cded3e67b1

openstack-dev/devstack,openstack-dev/devstack,noironetworks/devstack,dtroyer/devstack,group-policy/devstack,dtroyer/devstack,nawawi/openstack,noironetworks/devstack,nawawi/openstack,group-policy/devstack