Remove QXmlTestLogger constructor default param

This class is never constructed with the parameter defaulted.

Change-Id: If9c3f6562da1e48635a9cf5332bee7e9641255fa
Reviewed-on: http://codereview.qt.nokia.com/4021
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>

src/testlib/qxmltestlogger_p.h

@@ -63,7 +63,7 @@ class QXmlTestLogger : public QAbstractTestLogger
 public:
     enum XmlMode { Complete = 0, Light };
 
-    QXmlTestLogger(XmlMode mode = Complete);
+    QXmlTestLogger(XmlMode mode);
     ~QXmlTestLogger();
 
     void startLogging(const char *filename);