Update ga_api.php

If safemode is active in the php ini and you are unable to change it, with a shared hosting server for example. It is best to check it and if it's turned on, don't include the CURLOPT_FOLLOWLOCATION.

Or else codeignitor will throw this error:
Message: curl_setopt() [function.curl-setopt]: CURLOPT_FOLLOWLOCATION cannot be activated when safe_mode is enabled or an open_basedir is set