doc: set logical umask in process.umask example

0644 seems to be the desired mode for new files (as it is a very weird
umask), and to achieve that the correct umask would be 0022.

PR-URL: https://github.com/joyent/node/pull/8039
Reviewed-by: Trevor Norris <trev.norris@gmail.com>

doc/api/process.markdown

@@ -708,7 +708,7 @@ Sets or reads the process's file mode creation mask. Child processes inherit
 the mask from the parent process. Returns the old mask if `mask` argument is
 given, otherwise returns the current mask.
 
-    var oldmask, newmask = 0644;
+    var oldmask, newmask = 0022;
 
     oldmask = process.umask(newmask);
     console.log('Changed umask from: ' + oldmask.toString(8) +