Use proper storage method for writing skeleton files

otherwise the filecache will have a wrong size for skeleton files

Signed-off-by: Julius Härtl <jus@bitgrid.net>

lib/private/legacy/OC_Util.php

@@ -254,7 +254,7 @@ public static function copyr($source, \OCP\Files\Folder $target) {
 						closedir($dir);
 						return;
 					}
-					stream_copy_to_stream($sourceStream, $child->fopen('w'));
+					$child->putContent($sourceStream);
 				}
 			}
 		}