Fix fallback branch search in roomservice

If you provided a fallback branch to roomservice via the
ROOMSERVICE_BRANCHES environment var the branch search would fail
if the device repo had any tags.

Fixed this by appending the tag search results to the branch
search results instead of overwriting them

Change-Id: I73a11af1500bd04e346f08ec3f83454502f3a169
Merge remote branch 'cm/cm-10.1'