locks: make posix_test_lock() interface more consistent

Since posix_test_lock(), like fcntl() and ->lock(), indicates absence or
presence of a conflict lock by setting fl_type to, respectively, F_UNLCK
or something other than F_UNLCK, the return value is no longer needed.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 13ac6fa..c87dc71 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -402,7 +402,9 @@
 
 	lock_kernel();
 	/* Try local locking first */
-	if (posix_test_lock(filp, fl)) {
+	posix_test_lock(filp, fl);
+	if (fl->fl_type != F_UNLCK) {
+		/* found a conflict */
 		goto out;
 	}