QDBusMarshaller: ignore false-positive -Wformat-overflow gcc warning

Change-Id: Icd5d21ec7ebd16476a1070a18ac618b87575d5f6
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/dbus/qdbusmarshaller.cpp

@@ -237,8 +237,11 @@ inline QDBusMarshaller *QDBusMarshaller::beginMap(QMetaType kid, QMetaType vid)
         return this;
     }
     if (ksignature[1] != 0 || !QDBusUtil::isValidBasicType(*ksignature)) {
+QT_WARNING_PUSH
+QT_WARNING_DISABLE_GCC("-Wformat-overflow")
         qWarning("QDBusMarshaller: type '%s' (%d) cannot be used as the key type in a D-BUS map.",
                  kid.name(), kid.id());
+QT_WARNING_POP
         error("Type %1 passed in arguments cannot be used as a key in a map"_L1
               .arg(QLatin1StringView(kid.name())));
         return this;