LU-16067 debugfs: quiet debugfs 'catastrophic' message

LU-16067 debugfs: quiet debugfs 'catastrophic' message

When debugfs runs with the "-c" option, it prints a scary message:

    catastrophic mode - not reading inode or group bitmaps

that is often misunderstood by users to mean that there is something
wrong with the filesystem, when there is no problem at all.

Not reading the bitmaps is totally normal and expected behavior for
the "-c" option, which is used to significantly shorten the debugfs
command execution time by not reading metadata that isn't needed.

Since there is often confusion about what this message means, it
would be better to just avoid printing anything at all, since the
use of "-c" is expressly requesting this behavior, and there are
no messages printed out for other options.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I59b26a601780544ab995aa4ca7ab0c2123c70118
Reviewed-on: https://review.whamcloud.com/48109
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Artem Blagodarenko <ablagodarenko@ddn.com>
Reviewed-by: Li Dongyang <dongyangli@ddn.com>