fix endif comment

Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1079)

crypto/rand/rand_win.c

@@ -263,7 +263,7 @@ static void readscreen(void)
     /* Clean up */
     DeleteObject(hBitmap);
     ReleaseDC(NULL, hScrDC);
-# endif                         /* !OPENSSL_SYS_CYGWIN */
+# endif                         /* !OPENSSL_SYS_WIN32_CYGWIN */
 }
 
 #endif