Modify logging to use various logging levels

Related to rhbz#1001139.

Mapping:
      log = log_warning
VERB1 log = log_notice
VERB2 log = log_info
VERB3 log = log_debug
VERBn (p)error = (p)warn_msg

Signed-off-by: Richard Marko <rmarko@redhat.com>

mmilata: change should_log to static bool
Add journald support

Related to rhbz#1001139.

Signed-off-by: Richard Marko <rmarko@redhat.com>
Use log_ family instead of VERBn log calls

Mapping:
      log = log_warning
VERB1 log = log_notice
VERB2 log = log_info
VERB3 log = log_debug
VERBn (p)error = (p)warn_msg

Related to rhbz#1001139.

Signed-off-by: Richard Marko <rmarko@redhat.com>

mmilata: whitespace fixes
Merge branch 'rhbz1001139'