CBQE-0: fixing parse run_install param in run_job_linux.sh

Seen error scripts/run_job_linux.sh: 92: [: =: unexpected operator in
"http://qa.hq.northscale.net/view/3.0%20By%20COMPONENT/job/centos_x64--31_02--uniXDCR_SSL-P1/97/consoleFull"

Change-Id: I7bf19fa529f399df70d4677239b9153691ecf794
Reviewed-on: http://review.couchbase.org/43031
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>