[packages/rpm-build-tools] Non-fast-forward update to branch purge

[draenog]

The branch 'purge' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch.

Commits removed from the branch:

  97aad83... purge_packages: Add option to switch on/off git gc

Commits added to the branch:

  8bb800a... purge_packages: Add option to switch on/off git gc