Rename add_error methods: Django 1.7 conflict
Rename add_error methods: Django 1.7 conflict

In Django 1.7, Forms have an add_error() method and our definition
was conflicting with Django's method. Thanks to hertzog@debian.org
for the patch.

Close-bug: #1352919
Change-Id: I1f558cf7f3198a68629738a011e9cae0c3749320

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