Add coverage option to run_tests.sh
Add coverage option to run_tests.sh

This commit adds a new option to run_tests.sh to run the unit tests
with coverage enabled. If the coverage arg is specified a coverage
report will be generated after the unit tests are run.

Change-Id: I1473fe4da96aecd0b3b0bf3a3ec1e3e87039271b

Vaidyanath/tempest,pandeyop/tempest,hayderimran7/tempest,manasi24/tempest,rakeshmi/tempest,zsoltdudas/lis-tempest,vedujoshi/os_tempest,LIS/lis-tempest,pandeyop/tempest,roopali8/tempest,roopali8/tempest,pczerkas/tempest,neerja28/Tempest,masayukig/tempest,afaheem88/tempest,Juniper/tempest,JioCloud/tempest,jamielennox/tempest,vedujoshi/tempest,xbezdick/tempest,queria/my-tempest,sebrandon1/tempest,hpcloud-mon/tempest,Juniper/tempest,neerja28/Tempest,Tesora/tesora-tempest,varunarya10/tempest,tudorvio/tempest,vedujoshi/os_tempest,eggmaster/tempest,masayukig/tempest,manasi24/jiocloud-tempest-qatempest,bigswitch/tempest,queria/my-tempest,sebrandon1/tempest,vedujoshi/tempest,tonyli71/tempest,CiscoSystems/tempest,hayderimran7/tempest,manasi24/jiocloud-tempest-qatempest,Vaidyanath/tempest,jaspreetw/tempest,izadorozhna/tempest,JioCloud/tempest,cloudbase/lis-tempest,dkalashnik/tempest,tonyli71/tempest,redhat-cip/tempest,pczerkas/tempest,jamielennox/tempest,rakeshmi/tempest,BeenzSyed/tempest,Lilywei123/tempest,Mirantis/tempest,bigswitch/tempest,Juraci/tempest,flyingfish007/tempest,ebagdasa/tempest,izadorozhna/tempest,yamt/tempest,vmahuli/tempest,ntymtsiv/tempest,NexusIS/tempest,NexusIS/tempest,tudorvio/tempest,afaheem88/tempest_neutron,CiscoSystems/tempest,Lilywei123/tempest,cloudbase/lis-tempest,rzarzynski/tempest,Juraci/tempest,nunogt/tempest,jaspreetw/tempest,manasi24/tempest,ebagdasa/tempest,rzarzynski/tempest,afaheem88/tempest,LIS/lis-tempest,afaheem88/tempest_neutron,akash1808/tempest,alinbalutoiu/tempest,cisco-openstack/tempest,ntymtsiv/tempest,xbezdick/tempest,hpcloud-mon/tempest,akash1808/tempest,danielmellado/tempest,danielmellado/tempest,yamt/tempest,eggmaster/tempest,Mirantis/tempest,varunarya10/tempest,zsoltdudas/lis-tempest,vmahuli/tempest,nunogt/tempest,alinbalutoiu/tempest,dkalashnik/tempest,openstack/tempest,cisco-openstack/tempest,redhat-cip/tempest,FujitsuEnablingSoftwareTechnologyGmbH/tempest,BeenzSyed/tempest,openstack/tempest,Tesora/tesora-tempest,FujitsuEnablingSoftwareTechnologyGmbH/tempest,flyingfish007/tempest