Fix needing to call install command from same directory.

ServiceDescriptor.cs

@@ -36,8 +36,7 @@ namespace winsw
                 // this returns the executable name as given by the calling process, so
                 // it needs to be absolutized.
                 string p = Environment.GetCommandLineArgs()[0];
-                return Path.Combine(AppDomain.CurrentDomain.BaseDirectory, p);
-
+                return Path.GetFullPath(p);
             }
         }