usb-redir: Revert usb-redir part of commit 93bfef4c

Commit 93bfef4c6e4b23caea9d51e1099d06433d8835a4 makes qemu-devices
which report the qemu version string to the guest in some way use a
qemu_get_version function which reports a machine-specific version string.

However usb-redir does not expose the qemu version to the guest, only to
the usbredir-host as part of the initial handshake. This can then be logged
on the usbredir-host side for debugging purposes and is otherwise completely
unused! For debugging purposes it is important to have the real qemu version
in there, rather then the machine-specific version.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
