cleanup double repeated response.headers['X-Timestamp'] = file.metadata['X-Timestamp'] in swift.obj.server.HEAD
cleanup double repeated response.headers['X-Timestamp'] = file.metadata['X-Timestamp']
in swift.obj.server.HEAD

Change-Id: Ie7cf853319589db7c48836dd5d7fd5e68cb009cd

clayg/swift,mjzmjz/swift,rackerlabs/swift,JioCloud/swift,matthewoliver/swift,tipabu/swift,tsli/test,dencaval/swift,smerritt/swift,matthewoliver/swift,VictorLowther/swift,williamthegrey/swift,bradleypj823/swift,tsli/test,hbhdytf/mac2,smerritt/swift,notmyname/swift,aerwin3/swift,maginatics/swift,NeCTAR-RC/swift,matthewoliver/swift,nadeemsyed/swift,Khushbu27/Tutorial,takeshineshiro/swift,swiftstack/swift,hbhdytf/mac2,sarvesh-ranjan/swift,eatbyte/Swift,gold3bear/swift,notmyname/swift,clayg/swift,mjzmjz/swift,iostackproject/IO-Bandwidth-Differentiation,bkolli/swift,tipabu/swift,levythu/swift,clayg/swift,IPVL/swift-kilo,xiaoguoai/ec-dev-swift,redhat-openstack/swift,mjwtom/swift,dencaval/swift,openstack/swift,hurricanerix/swift,tipabu/swift,nadeemsyed/swift,psachin/swift,revoer/keystone-8.0.0,zaitcev/swift-lfs,openstack/swift,hurricanerix/swift,Mirantis/swift-encrypt,nadeemsyed/swift,smerritt/swift,bouncestorage/swift,hbhdytf/mac,matthewoliver/swift,citrix-openstack/build-swift,clayg/swift,psachin/swift,anishnarang/gswift,daasbank/swift,Khushbu27/Tutorial,JioCloud/swift,iostackproject/IO-Bandwidth-Differentiation,Akanoa/swift,VictorLowther/swift,aerwin3/swift,tipabu/swift,hbhdytf/mac2,swiftstack/swift,citrix-openstack/build-swift,zaitcev/swift-lfs,IPVL/swift-kilo,openstack/swift,anishnarang/gswift,Mirantis/swift-encrypt,notmyname/swift,Triv90/SwiftUml,Triv90/SwiftUml,redbo/swift,scality/ScalitySproxydSwift,AfonsoFGarcia/swift,thiagodasilva/swift,orion/swift-config,smerritt/swift,zackmdavis/swift,openstack/swift,citrix-openstack-build/swift,Seagate/swift,redbo/swift,psachin/swift,Seagate/swift,orion/swift-config,larsbutler/swift,xiaoguoai/ec-dev-swift,sarvesh-ranjan/swift,AfonsoFGarcia/swift,redhat-openstack/swift,psachin/swift,maginatics/swift,gold3bear/swift,shibaniahegde/OpenStak_swift,notmyname/swift,williamthegrey/swift,takeshineshiro/swift,wenhuizhang/swift,bradleypj823/swift,eatbyte/Swift,Akanoa/swift,daasbank/swift,hurricanerix/swift,rackerlabs/swift,bkolli/swift,nadeemsyed/swift,hbhdytf/mac2,levythu/swift,citrix-openstack-build/swift,prashanthpai/swift,Em-Pan/swift,Em-Pan/swift,thiagodasilva/swift,hurricanerix/swift,shibaniahegde/OpenStak_swift,bouncestorage/swift,dpgoetz/swift,larsbutler/swift,revoer/keystone-8.0.0,prashanthpai/swift,wenhuizhang/swift,scality/ScalitySproxydSwift,hbhdytf/mac,dpgoetz/swift,swiftstack/swift,zackmdavis/swift,mjwtom/swift,NeCTAR-RC/swift