Debugger: Only warn once about unhandled breakpoints

Don't show the dialog for every single breakpoint

Task-number: QTCREATORBUG-5557
Change-Id: Id1b60e92856cd2c8b81de43340bbaf4f5d7f3a8d
Reviewed-on: http://codereview.qt.nokia.com/2326
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Kai Koehne <kai.koehne@nokia.com>

src/plugins/debugger/debuggerrunner.cpp

@@ -262,6 +262,7 @@ void DebuggerRunControl::start()
             QErrorMessage *msgBox = new QErrorMessage(debuggerCore()->mainWindow());
             msgBox->setAttribute(Qt::WA_DeleteOnClose);
             msgBox->showMessage(warningMessage);
+            break;
         }
     }