Fix unicode error when assertMessageCount() fails
Fix unicode error when assertMessageCount() fails

When assertMessageCount() fails, we display the list of messages that
were included in the response. However because the messages are lazily
translated by default, this would fail and show the following error
instead:

 TypeError: sequence item 0: expected string, __proxy__ found

Change-Id: I1d2ed97b66428e0ee1aac783c8370ab3ea665b29
Closes-Bug: #1315031

Metaswitch/horizon,izadorozhna/dashboard_integration_tests,philoniare/horizon,NeCTAR-RC/horizon,NCI-Cloud/horizon,agileblaze/OpenStackTwoFactorAuthentication,liyitest/rr,endorphinl/horizon,CiscoSystems/horizon,ging/horizon,izadorozhna/dashboard_integration_tests,anthonydillon/horizon,nvoron23/avos,RudoCris/horizon,gerrive/horizon,liyitest/rr,davidcusatis/horizon,damien-dg/horizon,orbitfp7/horizon,Solinea/horizon,coreycb/horizon,Dark-Hacker/horizon,NeCTAR-RC/horizon,Hodorable/0602,wolverineav/horizon,froyobin/horizon,philoniare/horizon,icloudrnd/automation_tools,yeming233/horizon,eayunstack/horizon,redhat-cip/horizon,endorphinl/horizon-fork,NCI-Cloud/horizon,anthonydillon/horizon,agileblaze/OpenStackTwoFactorAuthentication,tsufiev/horizon,dan1/horizon-x509,doug-fish/horizon,newrocknj/horizon,idjaw/horizon,zouyapeng/horizon,Mirantis/mos-horizon,blueboxgroup/horizon,yjxtogo/horizon,Tesora/tesora-horizon,bigswitch/horizon,Mirantis/mos-horizon,vladryk/horizon,doug-fish/horizon,mdavid/horizon,Tesora/tesora-horizon,karthik-suresh/horizon,Metaswitch/horizon,CiscoSystems/avos,orbitfp7/horizon,mrunge/openstack_horizon,saydulk/horizon,Daniex/horizon,idjaw/horizon,blueboxgroup/horizon,ging/horizon,FNST-OpenStack/horizon,dan1/horizon-proto,redhat-openstack/horizon,luhanhan/horizon,nvoron23/avos,kfox1111/horizon,Dark-Hacker/horizon,vladryk/horizon,endorphinl/horizon,BiznetGIO/horizon,bac/horizon,mrunge/horizon_lib,doug-fish/horizon,coreycb/horizon,orbitfp7/horizon,RudoCris/horizon,xinwu/horizon,mrunge/openstack_horizon,sandvine/horizon,openstack/horizon,davidcusatis/horizon,takeshineshiro/horizon,kfox1111/horizon,liyitest/rr,Solinea/horizon,zouyapeng/horizon,dan1/horizon-x509,newrocknj/horizon,aaronorosen/horizon-congress,CiscoSystems/avos,mandeepdhami/horizon,dan1/horizon-proto,FNST-OpenStack/horizon,dan1/horizon-x509,sandvine/horizon,liyitest/rr,redhat-openstack/horizon,flochaz/horizon,zouyapeng/horizon,idjaw/horizon,agileblaze/OpenStackTwoFactorAuthentication,xme1226/horizon,xinwu/horizon,watonyweng/horizon,Tesora/tesora-horizon,davidcusatis/horizon,yjxtogo/horizon,newrocknj/horizon,ChameleonCloud/horizon,CiscoSystems/avos,henaras/horizon,mdavid/horizon,Daniex/horizon,mrunge/horizon,agileblaze/OpenStackTwoFactorAuthentication,mrunge/horizon_lib,newrocknj/horizon,anthonydillon/horizon,ChameleonCloud/horizon,kfox1111/horizon,mdavid/horizon,xinwu/horizon,henaras/horizon,VaneCloud/horizon,j4/horizon,blueboxgroup/horizon,NeCTAR-RC/horizon,saydulk/horizon,ging/horizon,BiznetGIO/horizon,Dark-Hacker/horizon,flochaz/horizon,froyobin/horizon,j4/horizon,NeCTAR-RC/horizon,wangxiangyu/horizon,dan1/horizon-proto,bac/horizon,maestro-hybrid-cloud/horizon,mandeepdhami/horizon,tsufiev/horizon,promptworks/horizon,pranavtendolkr/horizon,promptworks/horizon,davidcusatis/horizon,idjaw/horizon,Solinea/horizon,bigswitch/horizon,noironetworks/horizon,tsufiev/horizon,VaneCloud/horizon,mandeepdhami/horizon,blueboxgroup/horizon,nvoron23/avos,vladryk/horizon,saydulk/horizon,NCI-Cloud/horizon,froyobin/horizon,JioCloud/horizon,luhanhan/horizon,j4/horizon,aaronorosen/horizon-congress,noironetworks/horizon,gerrive/horizon,CiscoSystems/avos,pranavtendolkr/horizon,mandeepdhami/horizon,RudoCris/horizon,redhat-openstack/horizon,ging/horizon,takeshineshiro/horizon,Metaswitch/horizon,django-leonardo/horizon,karthik-suresh/horizon,flochaz/horizon,xinwu/horizon,wolverineav/horizon,promptworks/horizon,django-leonardo/horizon,openstack/horizon,icloudrnd/automation_tools,ChameleonCloud/horizon,NCI-Cloud/horizon,tqtran7/horizon,ChameleonCloud/horizon,flochaz/horizon,saydulk/horizon,Metaswitch/horizon,openstack/horizon,eayunstack/horizon,JioCloud/horizon,pranavtendolkr/horizon,django-leonardo/horizon,henaras/horizon,tqtran7/horizon,j4/horizon,karthik-suresh/horizon,tellesnobrega/horizon,redhat-cip/horizon,pranavtendolkr/horizon,tellesnobrega/horizon,mdavid/horizon,endorphinl/horizon-fork,tellesnobrega/horizon,doug-fish/horizon,endorphinl/horizon-fork,VaneCloud/horizon,mrunge/openstack_horizon,sandvine/horizon,noironetworks/horizon,JioCloud/horizon,wolverineav/horizon,BiznetGIO/horizon,maestro-hybrid-cloud/horizon,Tesora/tesora-horizon,yjxtogo/horizon,Hodorable/0602,dan1/horizon-x509,openstack/horizon,wangxiangyu/horizon,anthonydillon/horizon,Dark-Hacker/horizon,dan1/horizon-proto,Mirantis/mos-horizon,philoniare/horizon,tqtran7/horizon,gerrive/horizon,watonyweng/horizon,VaneCloud/horizon,orbitfp7/horizon,wolverineav/horizon,BiznetGIO/horizon,gerrive/horizon,tsufiev/horizon,redhat-cip/horizon,noironetworks/horizon,karthik-suresh/horizon,damien-dg/horizon,endorphinl/horizon-fork,Mirantis/mos-horizon,sandvine/horizon,eayunstack/horizon,Hodorable/0602,maestro-hybrid-cloud/horizon,FNST-OpenStack/horizon,Hodorable/0602,mrunge/horizon,takeshineshiro/horizon,coreycb/horizon,Daniex/horizon,luhanhan/horizon,tellesnobrega/horizon,zouyapeng/horizon,mrunge/horizon_lib,CiscoSystems/horizon,damien-dg/horizon,xme1226/horizon,icloudrnd/automation_tools,redhat-cip/horizon,maestro-hybrid-cloud/horizon,redhat-openstack/horizon,yeming233/horizon,watonyweng/horizon,coreycb/horizon,promptworks/horizon,yeming233/horizon,luhanhan/horizon,icloudrnd/automation_tools,CiscoSystems/horizon,Daniex/horizon,aaronorosen/horizon-congress,Solinea/horizon,tqtran7/horizon,philoniare/horizon,yjxtogo/horizon,bac/horizon,mrunge/horizon,damien-dg/horizon,wangxiangyu/horizon,yeming233/horizon,vladryk/horizon,takeshineshiro/horizon,nvoron23/avos,RudoCris/horizon,FNST-OpenStack/horizon,watonyweng/horizon,kfox1111/horizon,xme1226/horizon,bac/horizon,CiscoSystems/horizon,endorphinl/horizon,wangxiangyu/horizon,bigswitch/horizon,django-leonardo/horizon,endorphinl/horizon,bigswitch/horizon,henaras/horizon