geo-rep: Fixing issue with xsync upper limit

While identifying the file/dir to sync, xtime of the file was compared
with xsync_upper_limit as `xtime < xsync_upper_limit` After the sync,
xtime of parent directory is updated as stime. With the upper limit
condition, stime is updated as MIN(xtime_parent, xsync_upper_limit)

With this files will get missed if `xtime_of_file == xsync_upper_limit`

With this patch xtime_of_file is compared as
xtime_of_file <= xsync_upper_limit

BUG: 1138952
Change-Id: I469e8638ab6923e518022a539a19e2d040b60eb0
Signed-off-by: Aravinda VK <avishwan@redhat.com>
Reviewed-on: http://review.gluster.org/8439
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Kotresh HR <khiremat@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Reviewed-on: http://review.gluster.org/8644