staging/lustre: constify uuid argument of obd_uuid2str

This is only part of the original Lustre tree commit.
Main part of the original commit changes server code and is
unneeded at client side.

Lustre-change: http://review.whamcloud.com/6534
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3342Signed-off-by: JC Lafoucriere <jacques-charles.lafoucriere@cea.fr>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/lustre/lustre_user.h

@@ -446,7 +446,7 @@ static inline void obd_str2uuid(struct obd_uuid *uuid, const char *tmp)
 }
 
 /* For printf's only, make sure uuid is terminated */
-static inline char *obd_uuid2str(struct obd_uuid *uuid)
+static inline char *obd_uuid2str(const struct obd_uuid *uuid)
 {
 	if (uuid->uuid[sizeof(*uuid) - 1] != '\0') {
 		/* Obviously not safe, but for printfs, no real harm done...