qa/standalone/ceph-helpers.sh: Defining custom timeout for wait_for_clean()

qa/standalone/ceph-helpers.sh: Defining custom timeout for wait_for_clean()

The wait_for_clean() is using the default timeout aka 300sec = 5mn.

wait_for_clean() is trying to find a clean status within that timeout
_or_ reset its counter if any progress got made in between loops.

In a case where the cluster is sane, the recovery should be made in
shorter than 5mn but it the cluster died, waiting for 5mn for nothing is
unefficient.

This patch is about defining a custom timeout for a wait_for_clean() not
to wait much more that 1m30 (90sec). If no progress is made in that
period, there is very few chance this will read the a valid state
anyhow.

Signed-off-by: Erwan Velu <erwan@redhat.com>