Fix recent asset request timeout issue by commenting out (for now) the m_maxAssetRequestConcurrency mistakenly passed in as a timeout to SynchronousRestObjectRequester.MakeRequest()

For a long time, possibly forever, the m_maxAssetRequestConcurrency was mistakenly passed in as a 30 ms timeout rather than as a concurrent connection limiter.
This didn't come to light until the timeout was actually used in recent commit faf9ba53
Since this hasn't been operational for a long time and in release candidate phase, commenting it out for now though will need to revisit this.
Relates to http://opensimulator.org/mantis/view.php?id=7165