KNOWN BUGS: -1 +1
Save exit code $? at the beginning of the END block

Otherwise cleaning up by doing some system() calls garbles $? with
unwanted values.
xen-delete-image no more passes $CONFIG{hostname} as array to logprint_with_config

The deletion of failed attempts was logged to files named like
ARRAY(0xa9dd98).log because the hostname was passed twice, i.e. as
arrayref (which didn't hurt otherwise).