gd imageloadfont, verify error while reading header

when reading the header verify we get an error when the header is
invalid.

Signed-off-by: BlackEagle <ike.devolder@gmail.com>

ext/gd/tests/imageloadfont_end_of_file_while_reading_header.phpt

@@ -10,11 +10,19 @@ if (!extension_loaded('gd')) die("skip gd extension not available\n");
 --FILE--
 <?php
 $filename = dirname(__FILE__) .  '/font.gdf';
+
+// End of file while reading header
 $bin = "\x41\x41\x41\x41\x00\x00\x00\x00\x00\x00";
 $fp = fopen($filename, 'wb');
 fwrite($fp, $bin);
 fclose($fp);
+$font = imageloadfont($filename);
 
+// Error while reading header
+$bin = "\xe0\x00\x00\x00\x20\x00\x00\x00\x06\x00\x00\x00\x0a\x00\x00";
+$fp = fopen($filename, 'wb');
+fwrite($fp, $bin);
+fclose($fp);
 $font = imageloadfont($filename);
 ?>
 --CLEAN--
@@ -23,3 +31,5 @@ unlink(__DIR__.'/font.gdf');
 ?>
 --EXPECTF--
 Warning: imageloadfont(): End of file while reading header in %s on line %d
+
+Warning: imageloadfont(): End of file while reading header in %s on line %d