cpptools

Fix for auto completion in case of auto declaration inside if condition:

struct Foo { int bar; };
void func()
{
    if (auto s = new Foo)
        s->; // auto completion does not work
}

Task-number: QTCREATORBUG-13805
Change-Id: Ia1776e8cc04e6040a6bf5f43cf82cfd6ce6dde7a
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>