Catch and log exceptions in consumer

This patch adds a try except block around the APRSIS
consumer.  This gives us a chance to log the specific
exception, so we can see why the consumer failed.

aprsd/client/aprsis.py

@@ -126,7 +126,10 @@ class APRSISClient(base.APRSClient):
         return aprs_client
 
     def consumer(self, callback, blocking=False, immortal=False, raw=False):
+        try:
             self._client.consumer(
                 callback, blocking=blocking,
                 immortal=immortal, raw=raw,
             )
+        except Exception as e:
+            LOG.error(f"Exception in consumer: {e}")