Description:
------------
Php_oci_persistent_helper() calls php_oci_connection_rollback() without checking connection->needs_commit. This results in an unnecessary call to OCITransRollback() at the end of request for persistent connections.

Reproduce code:
---------------
<?php
  echo "<pre>";
  oci_internal_debug(1);
  $conn = oci_pconnect("hr", "hr", "//localhost/XE");
  $query = 'select * from dual';
  $stid = oci_parse($conn, $query);
  oci_execute($stid, OCI_DEFAULT);
  oci_rollback($conn);
  echo "</pre>";
?>

Expected result:
----------------
...
OCI8 DEBUG: OCITransRollback at (/tmp/php-5.1.3/ext/oci8/oci8.c:1400) 
OCI8 DEBUG: OCIStmtRelease at (/tmp/php-5.1.3/ext/oci8/oci8_statement.c:589) 
...


Actual result:
--------------
...
OCI8 DEBUG: OCITransRollback at (/tmp/php-5.1.3/ext/oci8/oci8.c:1400) 
OCI8 DEBUG: OCITransRollback at (/tmp/php-5.1.3/ext/oci8/oci8.c:1400) 
OCI8 DEBUG: OCIStmtRelease at (/tmp/php-5.1.3/ext/oci8/oci8_statement.c:589) 
...