log: also pass log_print through report and add log_print_bypass_report for use in libdm-report for direct print without report
log_print is used during cmd line processing to log the result of the
operation (e.g. "Volume group vg successfully changed" and similar).
We don't want output from log_print to be interleaved with current
reports from group where log is reported as well. Also, the information
printed by log_print belongs to the log report too, so it should be
rerouted to log report if it's set.
Since the code in libdm-report which is responsible for doing the report
output uses log_print too, we need to use a different kind of log_print
which bypasses any log report currently used for logging (...simply,
we can't call log_print to output the log report itself which in turn
would again reroute to report - the report would never get on output
this way).