Allow STATIC_URL override
Allow STATIC_URL override

When the change was committed to allow moving WEBROOT from '/',
STATIC_URL became hard-coded based on WEBROOT. This is an unnecessary
linking and breaks downstream packages.

This patch supports overriding STATIC_URL in local_settings.py and have
it honored by settings.py.

Closes-Bug: #1474551
Change-Id: Id0c5b2c6e4ff5f85ec94c5f474382664b303be23

karthik-suresh/horizon,NeCTAR-RC/horizon,FNST-OpenStack/horizon,takeshineshiro/horizon,redhat-openstack/horizon,noironetworks/horizon,redhat-cip/horizon,watonyweng/horizon,wolverineav/horizon,bac/horizon,gerrive/horizon,django-leonardo/horizon,takeshineshiro/horizon,noironetworks/horizon,redhat-cip/horizon,doug-fish/horizon,BiznetGIO/horizon,tqtran7/horizon,idjaw/horizon,endorphinl/horizon,bac/horizon,noironetworks/horizon,ChameleonCloud/horizon,django-leonardo/horizon,anthonydillon/horizon,sandvine/horizon,tqtran7/horizon,Mirantis/mos-horizon,saydulk/horizon,anthonydillon/horizon,xinwu/horizon,watonyweng/horizon,BiznetGIO/horizon,Dark-Hacker/horizon,saydulk/horizon,Tesora/tesora-horizon,takeshineshiro/horizon,davidcusatis/horizon,bigswitch/horizon,maestro-hybrid-cloud/horizon,mdavid/horizon,ChameleonCloud/horizon,wolverineav/horizon,mdavid/horizon,dan1/horizon-proto,dan1/horizon-proto,coreycb/horizon,karthik-suresh/horizon,redhat-cip/horizon,philoniare/horizon,xinwu/horizon,damien-dg/horizon,maestro-hybrid-cloud/horizon,endorphinl/horizon,coreycb/horizon,yeming233/horizon,anthonydillon/horizon,FNST-OpenStack/horizon,vladryk/horizon,saydulk/horizon,endorphinl/horizon-fork,sandvine/horizon,philoniare/horizon,BiznetGIO/horizon,noironetworks/horizon,redhat-openstack/horizon,tqtran7/horizon,ChameleonCloud/horizon,watonyweng/horizon,FNST-OpenStack/horizon,bigswitch/horizon,mdavid/horizon,FNST-OpenStack/horizon,endorphinl/horizon,redhat-openstack/horizon,davidcusatis/horizon,dan1/horizon-x509,sandvine/horizon,Mirantis/mos-horizon,endorphinl/horizon-fork,karthik-suresh/horizon,redhat-openstack/horizon,idjaw/horizon,yeming233/horizon,Dark-Hacker/horizon,endorphinl/horizon,xinwu/horizon,gerrive/horizon,yeming233/horizon,openstack/horizon,maestro-hybrid-cloud/horizon,dan1/horizon-proto,openstack/horizon,vladryk/horizon,vladryk/horizon,Mirantis/mos-horizon,idjaw/horizon,doug-fish/horizon,yeming233/horizon,bac/horizon,saydulk/horizon,damien-dg/horizon,NeCTAR-RC/horizon,redhat-cip/horizon,BiznetGIO/horizon,Tesora/tesora-horizon,damien-dg/horizon,takeshineshiro/horizon,watonyweng/horizon,Tesora/tesora-horizon,coreycb/horizon,doug-fish/horizon,doug-fish/horizon,bigswitch/horizon,bac/horizon,endorphinl/horizon-fork,karthik-suresh/horizon,gerrive/horizon,dan1/horizon-proto,bigswitch/horizon,idjaw/horizon,django-leonardo/horizon,davidcusatis/horizon,dan1/horizon-x509,mdavid/horizon,philoniare/horizon,dan1/horizon-x509,wolverineav/horizon,xinwu/horizon,Tesora/tesora-horizon,Dark-Hacker/horizon,damien-dg/horizon,endorphinl/horizon-fork,anthonydillon/horizon,coreycb/horizon,tqtran7/horizon,ChameleonCloud/horizon,django-leonardo/horizon,sandvine/horizon,maestro-hybrid-cloud/horizon,Dark-Hacker/horizon,philoniare/horizon,dan1/horizon-x509,openstack/horizon,NeCTAR-RC/horizon,Mirantis/mos-horizon,NeCTAR-RC/horizon,vladryk/horizon,gerrive/horizon,wolverineav/horizon,openstack/horizon,davidcusatis/horizon