Fix "failed to find recorded entry for 0" warnings.

Add a couple of checks to the data flow when updating a ProgramInfo
data structure. First, before sending a notification that a
ProgramInfo has changed ensure that the data structure actually
represents a recording (not a video, DVD, Bluray, or stream).  Second,
when receiving a MASTER_UPDATE_REC_INFO message verify that the
recording id number isn't zero.

Fixes #483.

(cherry picked from commit ecac941)

mythtv/libs/libmyth/programinfo.cpp

@@ -2758,7 +2758,8 @@ void ProgramInfo::UpdateLastPlayTimeStamp(bool hasLastPlay) const
 
 void ProgramInfo::SendUpdateEvent(void) const
 {
-    s_updater->insert(m_recordedId, kPIUpdate);
+    if (IsRecording())
+        s_updater->insert(m_recordedId, kPIUpdate);
 }
 
 void ProgramInfo::SendAddedEvent(void) const

mythtv/libs/libmyth/programinfoupdater.cpp

@@ -10,6 +10,8 @@
 void ProgramInfoUpdater::insert(
     uint     recordedid, PIAction action, uint64_t filesize)
 {
+    if (recordedid == 0)
+        return;
     QMutexLocker locker(&m_lock);
     if (kPIUpdate == action || kPIUpdateFileSize == action)
     {

mythtv/programs/mythbackend/mainserver.cpp

@@ -1524,6 +1524,8 @@ void MainServer::customEvent(QEvent *e)
             uint recordedid = 0;
             if (tokens.size() >= 2)
                 recordedid = tokens[1].toUInt();
+            if (recordedid == 0)
+                return;
 
             ProgramInfo evinfo(recordedid);
             if (evinfo.GetChanID())