Revert the changes of revision 12682 (PR#5644 Stream.count broken when used with Sapp or Slazy nodes) because of regressions identified by hongboz


git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13914 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
PR#5644: a dumbed-down fix to fix the observable effect (Stream.of_string) with no change to the underlying code (to avoid regressions)

As I learned the hard way, it is essentially impossible to get
a satisfying behavior in presence of a mix of updates, concatenations
and counts. The best thing to do is thus to not change anything
(a good way to preserve compatibility), and only fix the
Stream.of_string function to assume nothing of the count passed to the
[from] function.

I also modified the mli documentation of [Stream.from] to warn other
users of this potential pitfall.


git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13915 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02