Add .venv to git ignore
Add .venv to git ignore

.venv is used by run_test.sh so we don't need it in git at all

Change-Id: I53aecedf31d6092782d73ef7e3da756ecb892161

vganapath/rally,go-bears/rally,aplanas/rally,amit0701/rally,varunarya10/rally,eayunstack/rally,gluke77/rally,redhat-openstack/rally,vefimova/rally,cernops/rally,pyKun/rally,paboldin/rally,vefimova/rally,varunarya10/rally,aplanas/rally,shdowofdeath/rally,eayunstack/rally,go-bears/rally,paboldin/rally,gluke77/rally,yeming233/rally,aforalee/RRally,gluke77/rally,redhat-openstack/rally,pandeyop/rally,vganapath/rally,vponomaryov/rally,cernops/rally,group-policy/rally,eonpatapon/rally,vponomaryov/rally,openstack/rally,shdowofdeath/rally,afaheem88/rally,openstack/rally,amit0701/rally,pyKun/rally,gluke77/rally,group-policy/rally,group-policy/rally,amit0701/rally,ytsarev/rally,pandeyop/rally,afaheem88/rally,ytsarev/rally,vganapath/rally,openstack/rally,eonpatapon/rally,yeming233/rally,openstack/rally,aforalee/RRally,vganapath/rally,eayunstack/rally,paboldin/rally