Thanks Laszlo Ersek.

Previously the code would drop the first character in any sequence of
non-printing characters that occurred within a string.

Fix for commit e6f18c59d577dd0b443bc6a1d76f699c4e0dde9f.

Fix for commit e6f18c59d577dd0b443bc6a1d76f699c4e0dde9f.

Remove the data(keys) and log files of puppet.

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>

Change guestfs___first_line_of_file so that if the file is empty this
returns an empty string instead of an error.  This is consistent with
the behaviour of this function in the case where the file starts with
a \n character, where it would previously have returned an empty
string.

Change all callers so that they handle this case.

Then change the hostname parsing code so that it doesn't give up when
/etc/HOSTNAME is empty, but falls through to the next alternative, and
similarly for /etc/hostname.

Thanks Todd Mummert for finding and diagnosing this bug.

parse_release_file should be used to set fs->product_name, instead of
calling guestfs___first_line_of_file directory, although currently the
two are equivalent.

This is code motion and fixes
commit b648b1813fc8e55db790435b5414d9be3ec765d2.