Handle non-zero exit code from git diff

The check for a changed repo in setup_develop() 'git diff --exit-code'
returns a status of 1 when the repo has changes; trap that so errexit
does not abort the script.

Bug-Id: 1285780
Change-Id: Ic97e68348f46245b271567893b447fcedbd7bd6e
Fix Neutron enabled check

The pending revision to is_service_enabled() requires is_neutron_enabled() to
be declared before it is indirectly called in lib/neutron.  Also
exercises/volume.sh needs to source lib/neutron to do the check in ping_check().

Need to debug the Q_RR_COMMAND issue so xtrace through that bit.

Change-Id: I1c458aaa787ffb98c945aefc3afa80c6861a405f
remove if check

Change-Id: Iebe874c73defebdedb9e83d20bd54a1cf284a00d
Merge branch 'neutron-enabled' into dt-test
Merge branch 'fix-exit-trap' into dt-test
Merge branch 'fix-git-diff' into dt-test
Merge branch 'set-conf-dir' into dt-test
Merge branch 'test-service-functions' into dt-test