couple breakpoint listing with source listing

the assumption is that pending breakpoints will only be resolved when
the source list changes. consequently it is pointless to update just
one of them.

src/plugins/debugger/gdb/gdbengine.h

@@ -270,7 +270,6 @@ private: ////////// Inferior Management //////////
 
     // This should be always the last call in a function.
     Q_SLOT virtual void attemptBreakpointSynchronization();
-    void attemptBreakpointSynchronization2(const GdbResponse &);
 
     virtual void stepExec();
     virtual void stepOutExec();