Add manila.conf.sample to .gitignore
Add manila.conf.sample to .gitignore

tox job "genconfig" generates manila config sample
'etc/manila/manila.conf.sample' and it should be ignored by git.

Change-Id: Id34ff15ce9a4ce6da5b23c9d1e1ef21e96cc4413

sajuptpm/manila,vponomaryov/manila,bswartz/manila,openstack/manila,jcsp/manila,redhat-openstack/manila,weiting-chen/manila,scality/manila,scality/manila,bswartz/manila,jcsp/manila,openstack/manila,NetApp/manila,vponomaryov/manila,sajuptpm/manila,redhat-openstack/manila,NetApp/manila,weiting-chen/manila