JENKINS-8676 Windows XP slave stopped working in 1.396 (related to name change)

The ManagedWindowsServiceLauncher refers to hudson.exe and hudson-slave.exe while we renamed the artifact to jenkins.exe.

Tentative fix, completely untested (no windows box around).
Not sure about the service name (jenkinsslave). I added a second check for backward compatibility but I have no idea if it's useful.