Fixed bug introduced by preg_match change from php/php-src#1303

Author: gsherwood

CodeSniffer/Standards/PEAR/Sniffs/Commenting/FileCommentSniff.php

@@ -498,15 +498,13 @@ protected function processCopyright(PHP_CodeSniffer_File $phpcsFile, array $tags
             $matches = array();
             if (preg_match('/^([0-9]{4})((.{1})([0-9]{4}))? (.+)$/', $content, $matches) !== 0) {
                 // Check earliest-latest year order.
-                if ($matches[3] !== '') {
+                if ($matches[3] !== '' && $matches[3] !== NULL) {
                     if ($matches[3] !== '-') {
-                        var_dump($content);
-                        var_dump($matches);
                         $error = 'A hyphen must be used between the earliest and latest year';
                         $phpcsFile->addError($error, $tag, 'CopyrightHyphen');
                     }
 
-                    if ($matches[4] !== '' && $matches[4] < $matches[1]) {
+                    if ($matches[4] !== '' && $matches[4] !== NULL && $matches[4] < $matches[1]) {
                         $error = "Invalid year span \"$matches[1]$matches[3]$matches[4]\" found; consider \"$matches[4]-$matches[1]\" instead";
                         $phpcsFile->addWarning($error, $tag, 'InvalidCopyright');
                     }