[CBD-1191]: Add platform tag to jenkinsQm.pm for dashboard commit validation.

Change-Id: I11c47310d8eb367b08ecd66444f3fa5561961762
Reviewed-on: http://review.couchbase.org/34368
Reviewed-by: Eric Limare <eric.limare@couchbase.com>
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>