use upload_tmp_dir as temp place, see #297

We changed a line like this some time ago in upload/main

ext/rotate/main.php

@@ -179,7 +179,7 @@ class RotateImage extends Extension {
 		$image_rotated = imagerotate($image, $deg, 0);
 		
 		/* Temp storage while we rotate */
-		$tmp_filename = tempnam("/tmp", 'shimmie_rotate');
+		$tmp_filename = tempnam(ini_get('upload_tmp_dir'), 'shimmie_rotate');
 		if (empty($tmp_filename)) {
 			throw new ImageRotateException("Unable to save temporary image file.");
 		}