Fix mock==1.1.0 break test_raw_request_chunked
Fix mock==1.1.0 break test_raw_request_chunked

assert_call_count is not support in mock=1.1.0
change assert_call_count statement to 2 steps:
1. get the call count
2. use assertEqual instead

Change-Id: I15cade184403bcbd75f50f1f2074cebc924a96d3
Closes-Bug: #1473309

akash1808/tempest,roopali8/tempest,JioCloud/tempest,nunogt/tempest,hayderimran7/tempest,zsoltdudas/lis-tempest,varunarya10/tempest,vedujoshi/tempest,tudorvio/tempest,manasi24/tempest,pandeyop/tempest,flyingfish007/tempest,nunogt/tempest,flyingfish007/tempest,izadorozhna/tempest,JioCloud/tempest,openstack/tempest,redhat-cip/tempest,sebrandon1/tempest,pczerkas/tempest,redhat-cip/tempest,Juraci/tempest,alinbalutoiu/tempest,openstack/tempest,tonyli71/tempest,dkalashnik/tempest,bigswitch/tempest,tonyli71/tempest,manasi24/tempest,masayukig/tempest,dkalashnik/tempest,Juniper/tempest,manasi24/jiocloud-tempest-qatempest,akash1808/tempest,rakeshmi/tempest,LIS/lis-tempest,Tesora/tesora-tempest,cisco-openstack/tempest,NexusIS/tempest,pandeyop/tempest,Juniper/tempest,vedujoshi/tempest,xbezdick/tempest,manasi24/jiocloud-tempest-qatempest,masayukig/tempest,varunarya10/tempest,pczerkas/tempest,alinbalutoiu/tempest,tudorvio/tempest,hayderimran7/tempest,LIS/lis-tempest,Tesora/tesora-tempest,Juraci/tempest,xbezdick/tempest,bigswitch/tempest,rakeshmi/tempest,izadorozhna/tempest,sebrandon1/tempest,cisco-openstack/tempest,NexusIS/tempest,roopali8/tempest,zsoltdudas/lis-tempest