Ticket 48965 - Fix generation of the pre-release version
Description: Previously, when building DS from git checkout, pre-release
version didn't contain git commit id, though supporting code existed.
Fix description: Generate pre-release version according to Fedora Naming
Guidelines for snapshot packages [1]:
- change date format to YYYYMMDD
- remove '-' since it's not allowed
https://fedorahosted.org/389/ticket/48965
Reviewed by: mreynolds@redhat.com (Thanks!)
[1] https://fedoraproject.org/wiki/Packaging:Naming?rd=Packaging:NamingGuidelines#Snapshot_packages