Improve tools/make_test_data.sh correctness
Improve tools/make_test_data.sh correctness

This change allows the script tools/make_test_data.sh and
tools/make_test_data.py to work correctly by handing
exceptions appropriately.


Change-Id: Ib054c3e10d617686928bf03f94c5ff868905afde
Closes-bug: 1389684
openstack/ceilometer,pczerkas/aodh,r-mibu/ceilometer,fabian4/ceilometer,isyippee/ceilometer,Juniper/ceilometer,maestro-hybrid-cloud/ceilometer,pczerkas/aodh,pkilambi/ceilometer,chungg/aodh,mathslinux/ceilometer,eayunstack/ceilometer,ityaptin/ceilometer,fabian4/ceilometer,isyippee/ceilometer,ityaptin/ceilometer,chungg/aodh,sileht/aodh,redhat-openstack/ceilometer,idegtiarov/ceilometer,eayunstack/ceilometer,maestro-hybrid-cloud/ceilometer,cernops/ceilometer,openstack/aodh,pkilambi/ceilometer,redhat-openstack/ceilometer,mathslinux/ceilometer,r-mibu/ceilometer,Juniper/ceilometer,openstack/ceilometer,sileht/aodh,idegtiarov/ceilometer,openstack/aodh,cernops/ceilometer