patch 9.1.0780: MS-Windows: incorrect Win32 error checking

Problem:  MS-Windows: incorrect Win32 error checking
Solution: fix wrong order of error handling and perform
          some minor refactoring (Nir Lichtman)

In the function that adjusts the process privileges there is a mistake
in which GetLastError is called after CloseHandle, though clearly the
last error check is meant for the privileges related call before hand
and the current state appears like a mistake.

So fix this problem, and also perform the following:

- Remove the static variable done since the PlatformId is only called
  during initialization
- Fix incorrect parameter passed to the Win32 API privileges function

closes: #15845

Signed-off-by: Nir Lichtman <nir@lichtman.org>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    780,
 /**/
     779,
 /**/