Immutable rnrs hashtable

[Sjoerd van Leent Privé]

Hi all,

I might have found an issue using commit 
06906f370f77cbab520ff0d3c47449526934a9c8 (stable-2.0). I am attempting 
to do a hashtable-copy using rnrs hashtables, and set the mutable flag 
to #:t (according to documentation this should make it immutable, a bit 
odd). I attempted #:f as well. It appears the output hashtable is still 
mutable.

Can someone check this?

Regards,
Sjoerd