Clang: Do not warn about unhandled enum values

... in switch as long as there is a default case.

Change-Id: I584660cb26ee03a9ce3e41b297af0093dce59d1f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/cpptools/clangdiagnosticconfigsmodel.cpp

@@ -83,6 +83,7 @@ static void addConfigForAlmostEveryWarning(ClangDiagnosticConfigsModel &model)
         QStringLiteral("-Wno-gnu-zero-variadic-macro-arguments"),
         QStringLiteral("-Wno-documentation"),
         QStringLiteral("-Wno-shadow"),
+        QStringLiteral("-Wno-switch-enum"),
         QStringLiteral("-Wno-missing-prototypes"), // Not optimal for C projects.
         QStringLiteral("-Wno-used-but-marked-unused"), // e.g. QTest::qWait
     } + commonWarnings());