Limit tapctl.exe and openvpnmsica.dll to TAP-Windows6 adapters only

Limit tapctl.exe and openvpnmsica.dll to TAP-Windows6 adapters only

Note: Hardware ID check is used selectively. When naming the adapter, we
still need to check all existing adapters to prevent duplicate names.
When listing or removing adapters by name, the operation is limited to
TUN-Windows6 adapters only.

This patch follows Gert's recommendations from [openvpn-devel].

Signed-off-by: Simon Rozman <simon@rozman.si>
Message-ID: <20190120130813.GY962@greenie.muc.de>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20190224181621.27020-1-simon@rozman.si>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg18234.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>