mobile/GPS: fix two errors in the GPS handling

First, the time zone adjustment was wrong - this as written could only
ever have worked in UTC or by pure chance.

Second, the order of alerting the UI of the availability of a GPS fix
was also incorrect creating a race between the UI and our data
structures.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

mobile-widgets/qml/DiveDetailsEdit.qml

@@ -204,6 +204,7 @@ Item {
 				target: manager
 				onWaitingForPositionChanged: {
 					gpsText = manager.getCurrentPosition()
+					manager.appendTextToLog("received updated position info " + gpsText)
 				}
 			}