llvm-dwarfdump currently prints no message if decompression fails
for some reason. I noticed that during work on one of LLD patches
where LLD produced an broken output. It was a bit confusing to see
no output for section dumped and no any error message at all.
Patch adds error message for such cases.
Differential revision: https://reviews.llvm.org/D32865
llvm-svn: 302221
