features/gfid-access: Fix possible inode memory corruption.

        During lookup, the inode is not ref'd. Added code
        to ref the inode in call path and unref in cbk path.
        Also fixed a case where we should always be putting
        linked inode into context as it is not guaranteed
        that we get same inode that we passed in a call to
        inode_link.

Change-Id: Iaec083a9258658bef3047e83956729d3dbcd9a59
BUG: 1080295
Signed-off-by: Kotresh H R <khiremat@redhat.com>
Reviewed-on: http://review.gluster.org/7329
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Reviewed-by: Venky Shankar <vshankar@redhat.com>