Fix "Clear Override" to not create invalid rules.

Cherry-picked from master commit 6c2276f.

Fix RecordingInfo::ApplyRecordStateChange() to delete the underlying
rule instead of saving it when the new type is kNotRecording.
Previously, this would result in an invalid rule with type 0.

mythtv/libs/libmythtv/recordinginfo.cpp

@@ -518,7 +518,12 @@ void RecordingInfo::ApplyRecordStateChange(RecordingType newstate, bool save)
     record->m_type = newstate;
 
     if (save)
-        record->Save();
+    {
+        if (newstate == kNotRecording)
+            record->Delete();
+        else
+            record->Save();
+    }
 }
 
 /** \fn RecordingInfo::ApplyRecordRecPriorityChange(int)