staging: lustre: ldlm: remove unused 'overlaps' variable

'overlaps' is never used, only incremented.

Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>