Fix EXITFUNC back to process for the RCE too

Author: zeroSteiner

modules/exploits/windows/fileformat/cve_2017_8464_lnk_rce.rb

@@ -47,7 +47,7 @@ def initialize(info = {})
           ],
         'DefaultOptions'  =>
           {
-            'EXITFUNC'    => 'thread'
+            'EXITFUNC'    => 'process'
           },
         'Arch'            => [ARCH_X86, ARCH_X64],
         'Payload'         =>