ec: Fix incorrect management of healed bricks

The final lookup made to restore final file attributes after a self-heal
did clear the mask of bad bricks, causing that the final setattr won't
modify any brick at all. This caused that some attriutes, specially the
modification time of the file didn't get updated properly.

Now the mask of healed bricks is saved before doing the last lookup.
It's also used to correctly report the repaired bricks.

This is a backport of http://review.gluster.org/8905/

Change-Id: Ib94083c9e1b562515dfb54f9574120f1f031dccc
BUG: 1149725
Signed-off-by: Xavier Hernandez <xhernandez@datalab.es>
Reviewed-on: http://review.gluster.org/8906
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>