Add error handling for Frontend UPnP autodetection.

This adds an error handling block to UPnP detection of the Frontend
connection class, to allow the remainder of the list to be returned if
one machine responding to the query cannot be connected to.
(cherry picked from commit 8c9fc7a)

mythtv/bindings/python/MythTV/connections.py

@@ -468,7 +468,10 @@ def fromUPNP(cls, timeout=5):
         for res in msearch.searchMythFE(timeout):
             ip, port = reLOC.match(res['location']).group(1,2)
             port = 6546
-            yield cls(ip, port)
+            try:
+                yield cls(ip, port)
+            except MythFEError:
+                pass
 
     @classmethod
     def testList(cls, felist):