tst_QSettings: add missing () around a macro argument use

'val' was set to
   QList<...>() << ... << ...
further down.

Fixes a Clang warning.

Change-Id: I5fe80d87dbe2c1d50652dfd7b6c5f4a9198cd467
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

tests/auto/corelib/io/qsettings/tst_qsettings.cpp

@@ -2467,7 +2467,7 @@ void tst_QSettings::testEscapes()
         QString s = QSettingsPrivate::variantToString(v); \
         QCOMPARE(s, escStr); \
         QCOMPARE(QVariant(QSettingsPrivate::stringToVariant(escStr)), v); \
-        QVERIFY(val == v.func()); \
+        QVERIFY((val) == v.func());                                     \
     }
 
 #define testBadEscape(escStr, vStr) \