Clang: Fix warning about unused function

Last use was eliminated with

    commit b6e12f4a1c
    Convert macros from plain QByteArray to a vector of structs

Change-Id: I512524839199bc5c8b64f739636e9caebc37c7d0
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp

@@ -58,9 +58,6 @@ using namespace ClangCodeModel::Internal;
 
 namespace {
 
-QString _(const char text[])
-{ return QString::fromUtf8(text); }
-
 QString qrcPath(const QByteArray relativeFilePath)
 { return QLatin1String(":/unittests/ClangCodeModel/") + QString::fromUtf8(relativeFilePath); }