Log boot.py exceptions
Log boot.py exceptions

If boot.py fails with an exception, log it to syslog. In case the
exception is failing to remove the hostname file, it just means the
node isn't marked for reinstallation, so in this case log severity is
INFO. In case some other exception occurs, it's probably a more
serious error, and in that case the severity is ERR.

CSC-IT-Center-for-Science/ansible-role-pxe_bootstrap,CSC-IT-Center-for-Science/ansible-role-pxe_bootstrap