[cairo-path] Return CAIRO_STATUS_SUCCESS.

If we have already returned the error status, then it is cleaner (and
the common idiom) to use 'return CAIRO_STATUS_SUCCESS' rather than
'return status'.

src/cairo-path.c

@@ -339,7 +339,7 @@ _cairo_path_populate (cairo_path_t		*path,
     /* Sanity check the count */
     assert (cpp.data - path->data == path->num_data);
 
-    return status;
+    return CAIRO_STATUS_SUCCESS;
 }
 
 cairo_path_t *