Alarm support in HBase Part 1
Alarm support in HBase Part 1

Two additional tables are introduced for alarms and alarm_history.
Ordering in alarm_history was achived by that fact that HBase
stores entries in alphabetical order. It is needed to enlarge the
preciseness of reverse_timestamp because alarms history entries may be
generated once per second, especially in tests.

Partially implements bp hbase-alarming

Change-Id: I41bc60f13779899af0e8f8e01f85b2ee6d1c8aae

openstack/ceilometer,sileht/aodh,fabian4/ceilometer,MisterPup/Ceilometer-Juno-Extension,r-mibu/ceilometer,ityaptin/ceilometer,froyobin/ceilometer,NeCTAR-RC/ceilometer,eayunstack/ceilometer,cernops/ceilometer,openstack/ceilometer,isyippee/ceilometer,redhat-openstack/ceilometer,openstack/aodh,NeCTAR-RC/ceilometer,eayunstack/ceilometer,pczerkas/aodh,luogangyi/Ceilometer-oVirt,luogangyi/Ceilometer-oVirt,pkilambi/ceilometer,MisterPup/Ceilometer-Juno-Extension,idegtiarov/ceilometer,sileht/aodh,cernops/ceilometer,froyobin/ceilometer,Juniper/ceilometer,maestro-hybrid-cloud/ceilometer,isyippee/ceilometer,openstack/aodh,mathslinux/ceilometer,redhat-openstack/ceilometer,m1093782566/openstack_org_ceilometer,tanglei528/ceilometer,tanglei528/ceilometer,fabian4/ceilometer,Juniper/ceilometer,chungg/aodh,ityaptin/ceilometer,r-mibu/ceilometer,pkilambi/ceilometer,pczerkas/aodh,tanglei528/ceilometer,chungg/aodh,maestro-hybrid-cloud/ceilometer,idegtiarov/ceilometer,NeCTAR-RC/ceilometer,m1093782566/openstack_org_ceilometer,mathslinux/ceilometer