Use single quotes in PHP code

Fixes #12405

Signed-off-by: Michal Čihař <michal@cihar.com>

ChangeLog

@@ -20,6 +20,7 @@ phpMyAdmin - ChangeLog
 - issue #12292 Unable to edit transformations
 - issue #12502 Remove unused paramenter when connecting to MySQLi
 - issue #12303 Fix number formatting with different settings of precision in PHP
+- issue #12405 Use single quotes in PHP code
 
 4.6.4 (2016-08-16)
 - issue        [security] Weaknesses with cookie encryption, see PMASA-2016-29

libraries/Util.php

@@ -1167,7 +1167,7 @@ class Util
             }
 
             if (! empty($GLOBALS['show_as_php'])) {
-                $query_base = '$sql  = "' . $query_base;
+                $query_base = '$sql  = \'' . $query_base;
             } elseif (isset($query_base)) {
                 $query_base = self::formatSql($query_base);
             }
@@ -1311,7 +1311,7 @@ class Util
 
             //Clean up the end of the PHP
             if (! empty($GLOBALS['show_as_php'])) {
-                $retval .= '";';
+                $retval .= '\';';
             }
             $retval .= '</div>';