[llvm-dwarfdump] - Print an error message if section decompression failed.

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