rootfs.py: Unify _log_check_warn() and _log_check_error()
Use a common _log_check_common() function (based on the old
_log_check_warn() function) to implement the logic for both
_log_check_warn() and _log_check_error().
The main benefit of this is that now all error messages will be
reported again, not just the first one found. Additionally the output
will now look the same for both error and warning messages.
This removes the context for the error messages. However, since there
was no indication in the output that some of the lines were context,
they were more confusing than helping.
Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
