shell-completions: systemd-analyze set-log-level
Disallow invalid UTF-8 configuration

It is best to catch such errors early. If invalid UTF-8 ends up being
given to dbus methods, the program will crash:

process 20801: arguments to dbus_message_iter_append_basic() were incorrect, assertion "_dbus_check_is_valid_utf8 (*string_p)" failed in file dbus-message.c line 2598.
logind: be more verbose on errors
logind-session.c: use _cleanup_
blcokio bandwidth: add missing set of CGroupBlockIODeviceBandwidth's read

BlockIOReadBandwidth and BlockIOWriteBandwidth both use
config_parse_blockio_bandwidth to set up CGroupBlockIODeviceBandwidth,
We should set the read value based on the left values
in config files.
device cgroup: don't create a new CGroupDeviceAllow when it already in the list

If a device node is already in the device_allow list of
CGroupContext, we should replace it instead of create a
new one and append this new one to the end of device_allow
list.

change from v1: use streq to replace !strcmp
cgroup: only check once when mode is UNIT_CHECK

If the mode is UNIT_CHECK,it means we only want to check if
the paramaters are valid. the first round of cycle already
did this check, no need to check again.