CBQE-0: handle error when ini file not found

in scripts/run_job_linux.sh

Change-Id: If68bae12102b44551dbf9a8caddd63a3f721ce7a
Reviewed-on: http://review.couchbase.org/37262
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>