Support Source: lines in specs just like Source0:
Support Source: lines in specs just like Source0:

We used to only support Source0: lines in the spec file. However,
Source: is a valid synonym of Source0:, and it is used in some
contexts (e.g. rpm-packaging project).

Change-Id: Icb323997bbcf6485a767c5aa5728460478d8e473

openstack-packages/DLRN,openstack-packages/delorean,openstack-packages/delorean,openstack-packages/DLRN