bug#11328: 24.1.50; Comment in `dired-copy-file-recursive' code

["Drew Adams" <drew.adams@oracle.com>]

Oh, and since there is no doc string it might be a good idea to use better
parameter names.  There is a reason that for `copy-file' and
`make-symbolic-link' the parameter is called OK-IF-ALREADY-EXISTS and not simply
OK-FLAG.  (Same problem for `dired-copy-file'.)  You can guess the meaning from
OK-IF-ALREADY-EXISTS.

You are not helping readers of the code if they need to examine it all closely
to determine what a given parameter does.  In that case, you might as well name
the parameters X1, X2, X3, X4, X5, and X6.

And it's generally a good idea to use the same parameter names when you just
pass the arguments to another function and they have the same meaning.  If you
just pass PRESERVE-TIME to `copy-directory' and `copy-file', then use the same
name they use: KEEP-TIME.  (Or change all three and any other functions related
so they use the same names.)