qa: bump up scrub status command timeout

qa: bump up scrub status command timeout

A journal flush sometimes takes more than 120 seconds and so the 'scrub
status' command after blocking for more than 120 seconds is declared
failed causing the job to be declared as failed.

This bumping up of the timeout gives more time for the 'scrub status'
command to wait and eventually let the journal flush to complete.

Fixes: https://tracker.ceph.com/issues/63411
Signed-off-by: Milind Changire <mchangir@redhat.com>