SetComputerNameExW Fix Caused Regression in Hostname

reactos-bootcd-0.4.13-dev-267  for PR#1583 caused a regression in the Hostname functions. The System Setup used the SetComputerNameExW for setting the Hostname previously and now it sets the "NV Hostname", so the Hostname is left at its registry default. The attached patch fixes this problem. I have attached a working test program that I plan to submit later as a regression test. Thanks.