NFSv4.2: fix error return on memory allocation failure

Currently when an alloc_page fails the error return is not set in
variable err and a garbage initialized value is returned. Fix this
by setting err to -ENOMEM before taking the error return path.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: a1f26739 ("NFSv4.2: improve page handling for GETXATTR")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs42proc.c

@@ -1301,6 +1301,7 @@ ssize_t nfs42_proc_getxattr(struct inode *inode, const char *name,
 		pages[i] = alloc_page(GFP_KERNEL);
 		if (!pages[i]) {
 			np = i + 1;
+			err = -ENOMEM;
 			goto out;
 		}
 	}