[patch] sanity check bfd_is_section_compressed header

[DJ Delorie]

> Heh. I guess it's my fault, then, but I think it's clearly wrong to
> try to decompress a .debug_* section, especially given that its
> contents might legitimately begin with the magic string "ZLIB". I
> think we were just trying to be tolerant there.

I did some digging and it looks like nothing in binutils will generate
a .debug_* section that's compressed.  Can other tools do so?  Did I
miss anything?  If there can't be a compressed .debug_* "in the wild"
then I think removing the check for .debug_* in that snippet is
the right change.

Of course, the sanity check might be useful *also* :-)

Suggestions?