NFS: Trim extra slash in v4 nfs_path

A NFSv4 mount of a subdirectory will show an extra slash (as in
'server://path') in proc's mountinfo which will not match the device name
and path.  This can cause problems for programs searching for the mount.
Fix this by checking for a leading slash in the dentry path, if so trim
away any trailing slashes in the device name.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/namespace.c

@@ -98,7 +98,7 @@ char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen,
 		return end;
 	}
 	namelen = strlen(base);
-	if (flags & NFS_PATH_CANONICAL) {
+	if (*end == '/') {
 		/* Strip off excess slashes in base string */
 		while (namelen > 0 && base[namelen - 1] == '/')
 			namelen--;