gfapi: Closed the logfile fd in glfs_fini

The logfile fd is not closed even after calling glfs_fini,
hence in smb mount if connection to glusterfs volume fails
at a point after the log file was opened, the fd would remain
open until the process dies.

This patch closes the logfile fd in glfs_fini.

Change-Id: I608bfac9c6833b42750b0383ad26fd33ee378ee1
BUG: 1030228
Signed-off-by: Poornima <pgurusid@redhat.com>
Reviewed-on: http://review.gluster.org/6263
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>