(unfinished) test service functions

Change-Id: I3f4628b8dd55fa7819e7b697fe621861a582bbbc
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
Fix exit_trap() error if no child processes

Bug-Id: 1285776
Change-Id: Iad7a9f2c03cc39159beda55345f232cefed10520
Merge branch 'neutron-enabled' into dt-test
Merge branch 'fix-exit-trap' into dt-test
Merge branch 'set-conf-dir' into dt-test
Merge branch 'test-service-functions' into dt-test