Rise up salt's gather job timeout

While the minions are working their jobs the CLI is waiting for the
first initial timeout period (timeout) to start. When that hits,
the CLI sends sends the first "find_job" query. This kicks off the
gather_job_timeout timer. Sometimes a minion doesn't respond to the request
within the gather_job_timeout time period (default is 10s), so rise up
this value to give a chance for a minion to report actual status.

Change-Id: Ic3756b82fdeb17718870ab30e9578263d25309f7
Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>