xfs: recalculate summary counters at mount time if icount is bad

Since the sb write verifier trips on bad icounts, we should also force a
mount time recalculation of the summary counters if the icount is bad.
This helps us avoid blowing up at freeze/unmount time when the bad
counter gets written back out.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>