Remove warnings.

git-svn-id: http://subversion.jackaudio.org/jack/jack2/trunk/jackmp@4015 0c269be4-1314-0410-8aa9-9f06e86f4224

common/JackPhysicalMidiInput.h

@@ -120,7 +120,7 @@ namespace Jack {
     public:
 
         JackPhysicalMidiInput(size_t buffer_size=1024);
-        ~JackPhysicalMidiInput();
+        virtual ~JackPhysicalMidiInput();
 
         /**
          * Called to process MIDI data during a period.

common/JackPhysicalMidiOutput.h

@@ -92,7 +92,7 @@ namespace Jack {
 
         JackPhysicalMidiOutput(size_t non_rt_buffer_size=1024,
                                size_t rt_buffer_size=64);
-        ~JackPhysicalMidiOutput();
+        virtual ~JackPhysicalMidiOutput();
 
         /**
          * Called to process MIDI data during a period.