CBQE-0: do not override run_install in downstream jobs

if upstream job run_install=True then downsteam jobs use their default values(True/False)

Change-Id: I404a2f081083f4bdef91853f201e667edca66dda
Reviewed-on: http://review.couchbase.org/37376
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>