jjb/common: run-test-short: only use lavacli tags

jjb/common: run-test-short: only use lavacli tags

Only pass tags that were queried from the LAVA devices themselves,
don't add any additional tags (e.g. "weston")

This is done since after recent changes to releng-scripts, using
--device-tags will *require* those tags to be present for a given
device for the job to run, and currently no devices are using the
"weston" tag.

How to properly handle the -nogfx builds for boards with no
display/gfx needs to be revisited after proper tag handling is merged.

Change-Id: Ic6ba4743866c5de35ee45063c834c569c4b728eb
Signed-off-by: Kevin Hilman <khilman@baylibre.com>