fix usage of PDO::PGSQL_ATTR_DISABLE_PREPARES for pdo_pgsql extension setups...

fix usage of PDO::PGSQL_ATTR_DISABLE_PREPARES for pdo_pgsql extension setups not built from PHP core

fixes #2249

lib/Doctrine/DBAL/Driver/PDOPgSql/Driver.php

@@ -45,7 +45,7 @@ class Driver extends AbstractPostgreSQLDriver
                 $driverOptions
             );
 
-            if (PHP_VERSION_ID >= 50600
+            if (defined('PDO::PGSQL_ATTR_DISABLE_PREPARES')
                 && (! isset($driverOptions[PDO::PGSQL_ATTR_DISABLE_PREPARES])
                     || true === $driverOptions[PDO::PGSQL_ATTR_DISABLE_PREPARES]
                 )

tests/Doctrine/Tests/DBAL/Driver/PDOPgSql/DriverTest.php

@@ -107,7 +107,7 @@ class DriverTest extends AbstractPostgreSQLDriverTest
      */
     private function skipWhenNotUsingPhp56AndPdoPgsql()
     {
-        if (PHP_VERSION_ID < 50600) {
+        if (! defined('PDO::PGSQL_ATTR_DISABLE_PREPARES')) {
             $this->markTestSkipped('Test requires PHP 5.6+');
         }