Fixed ODBC on Win64.

The SQLGetConnectAttr() function can write up to 64-bit integers, as documented by MSDN here: http://msdn.microsoft.com/en-us/library/ms710297%28v=vs.85%29.aspx
This fix uses 64-bit integers instead of 32-bit ones, the original code corrupted the stack when used on win7-x64 with MSSQL 2008.

Tested on Win7-x64 with MSSQL 2008, I don't have the infrastructure required to test this change against the other SQL engines.