VIM: remove unnecessary (and invalid) cast.

fakevimhandler.cpp:941:43: warning: comparison of integers of different signs: 'Int' (aka 'unsigned int') and 'int' [-Wsign-compare]
        return m_xkey == c && m_modifiers != int(HostOsInfo::controlModifier());
                                      ~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Change-Id: I360873f0c74512d95ca8ecaac4f1ab0a477877e7
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>