Bug #897054: stack crashes with AttributeError on e.reason if the server returns an error
Bug #897054: stack crashes with AttributeError on e.reason if the server returns an error

Swap the URLError and HTTPError exception handlers.  HTTPError is a subclass
of URLError, so the HTTPError handler wasn't being reached.

Change-Id: Iec86d2b345dbd37858af888bbd54a74884025eda

n0ano/ganttclient