[Bug: 21.5-b28] open a gzipped file w/ jka-compr gives modified buffer

[Stephen J. Turnbull]

Vladimir G. Ivanovic writes:

 > Yes, this behavior has been present for quite a while, but I'm not 
 > sure that it's a bug.

It's a bug.

 > The buffer (a compressed file) has been modified (contents replaced
 > with an uncompressed version).

True, but this should be analogous to what happens when I read a
Japanese file into a buffer.