getlantern/lantern#1895 Stopping old connection pool when restarting ser...

...ver
No.  The primary cause of the CPU spike in production was in connpool, specifically [this code](https://github.com/getlantern/connpool/blob/master/connpool.go#L113).

The cause of the other CPU spike that I was in my testing was some code in the new connpool and that was fixed by [this change](https://github.com/getlantern/connpool/commit/aadaf20624407998883f72dd07bb4f9aee3376df#diff-f028e4a30aa4a70ee5f2c57baf44f65d).

Making session caching work is just gravy.