cluster/afr: Link inode only on lookup

Problem:
When "gluster volume heal <volname> info is executed, crawl's
process_entry is not going to populate iatt structure so the
iatt's gfid will be empty. So inode_links are failing.

Fix:
inode_link should be done only after lookup i.e. when heal is
performed. So moved the inode_link related code to just after
the lookup which is triggered when self-heal is done.

Tests:
The testcase that gives this issue does not give the inode-link
failures anymore. glustershd heal, info commands are working as
expected.
Wrote basic automation tests for proactive-self-heal-daemon
https://github.com/pranithk/gluster-tests/blob/master/afr/proactive-self-heal.sh

Change-Id: Ic112bf104a4d553a64d3d8559f681a25ae1a5362
BUG: 861015
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/4090
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>