PHP-1071: Create Index test can segfault

There is no retval to cleanup when exception is thrown
Merge pull request #671 from bjori/broken-test

There is no retval to cleanup when exception is thrown

* bjori/broken-test:
  PHP-1071: Create Index test can segfault
PHP-1065: Fix double free() when OP_GET_MORE fails

This is a bad copy&paste from the normal MongoCursor ctor
PHP-1065: Don't try to kill cursor that don't have a connection
Add a testcase for PHP-1065