SIT-upstream samba: Add support to trigger sit testing with proposed upstream devel patches

[spuiuk]

Integrate sit-testing with proposed upstream devel packages to ensure that the proposed patches do not break samba-cluster. The testing should be done only for the cephfs environment for the timebeing.

PR #94 opened to download and install the samba sources with the proposed devel packages.
Points to work already done by Anoop to integrate with gitlab.

[xhernandez]

@spuiuk #94 is already merged, so I think this issue should be closed. Is anything else pending ?