Remove duplicate X-Backend-Storage-Policy-Index key
Remove duplicate X-Backend-Storage-Policy-Index key

There is duplicate 'X-Backend-Storage-Policy-Index' dictionary key in unit.obj.test_server.py.
One key has fixed policy index value, and another has random value.
Unittest should done with random policy index, so remove key which is set fixed value.

Change-Id: Ic91fcf44d48297d0feee33c928ca682def9790a3

Akanoa/swift,levythu/swift,psachin/swift,smerritt/swift,notmyname/swift,nadeemsyed/swift,hbhdytf/mac,aerwin3/swift,tipabu/swift,redbo/swift,hurricanerix/swift,swiftstack/swift,tipabu/swift,prashanthpai/swift,clayg/swift,mjwtom/swift,matthewoliver/swift,bkolli/swift,hbhdytf/mac2,smerritt/swift,matthewoliver/swift,nadeemsyed/swift,Em-Pan/swift,larsbutler/swift,revoer/keystone-8.0.0,redbo/swift,openstack/swift,hbhdytf/mac,dencaval/swift,dencaval/swift,Akanoa/swift,hurricanerix/swift,levythu/swift,nadeemsyed/swift,prashanthpai/swift,openstack/swift,psachin/swift,rackerlabs/swift,openstack/swift,hbhdytf/mac2,bkolli/swift,takeshineshiro/swift,notmyname/swift,smerritt/swift,williamthegrey/swift,hbhdytf/mac2,larsbutler/swift,hbhdytf/mac2,clayg/swift,revoer/keystone-8.0.0,nadeemsyed/swift,mjwtom/swift,daasbank/swift,clayg/swift,rackerlabs/swift,daasbank/swift,smerritt/swift,notmyname/swift,tipabu/swift,Em-Pan/swift,aerwin3/swift,hurricanerix/swift,openstack/swift,thiagodasilva/swift,hurricanerix/swift,tipabu/swift,williamthegrey/swift,notmyname/swift,clayg/swift,matthewoliver/swift,psachin/swift,thiagodasilva/swift,swiftstack/swift,matthewoliver/swift,takeshineshiro/swift,psachin/swift,swiftstack/swift