convert_python_value: For uuid, don't check python version

For uuid, don't check `PY_MAJOR_VERSION >= 2 and PY_MINOR_VERSION >= 5`.

This is incorrect for Python 3.3. I think you copied it from another part of the code (I removed it in https://github.com/pymssql/pymssql/commit/1fe0ea1)

Since we don't support Python < 2.6, we can just remove this check.