add default for first Channel::createChannel()

default for first form which calls the second

src/client/pv/pvAccess.h

@@ -934,7 +934,7 @@ public:
      * @return <code>Channel</code> instance. If channel does not exist <code>null</code> is returned and <code>channelRequester</code> notified.
      */
     virtual Channel::shared_pointer createChannel(std::string const & channelName,ChannelRequester::shared_pointer const & channelRequester,
-            short priority = PRIORITY_DEFAULT) = 0;
+            short priority = PRIORITY_DEFAULT);
 
     /**
      * Create a channel.

src/factory/ChannelAccessFactory.cpp

@@ -115,6 +115,14 @@ epicsShareFunc void unregisterAllChannelProviderFactory()
 }
 
 
+Channel::shared_pointer
+ChannelProvider::createChannel(std::string const & channelName,
+                               ChannelRequester::shared_pointer const & channelRequester,
+                               short priority)
+{
+    return createChannel(channelName, channelRequester, priority, "");
+}
+
 }
 }