ceph: fix uninitialized err variable

Fixes warning
fs/ceph/xattr.c: In function '__build_xattrs':
fs/ceph/xattr.c:353: warning: 'err' may be used uninitialized in this function

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 65b3a84..1a48a55 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -350,7 +350,7 @@
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	int xattr_version;
 	struct ceph_inode_xattr **xattrs = NULL;
-	int err;
+	int err = 0;
 	int i;
 
 	dout("__build_xattrs() len=%d\n",