Restore old SIGPIPE handler in a proxy server test.
Restore old SIGPIPE handler in a proxy server test.

I think not doing this was setting the SIGPIPE handler to signal.SIG_DFL
instead of the Python default of signal.SIG_IGN.  This could cause other
tests which make a client stop reading before all data "chunks" are read
to fail harder than they should (i.e. the SIGPIPE there is benign and
even expected--the other side of the socket really did get closed
early).

Change-Id: I946a1913714a34ec677b701a2b5724bc8b715f70

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