Logging: Change the default log provider to systemd journal.

Logging: Change the default log provider to systemd journal.

This change replaces the default logging mechanism in the whole security
manager. The dlog provider is not used anymore and it is also excluded from
being build along with the project. Its sources should stay untouched by now.

To verify, first please install this together with the latest security-tests
package. When installed, run tests:
  # security-manager-tests --output=text

And after that please check for the presence of traces in journal:
  # journalctl --unit=security-manager.service

Please also check for the presence of security-manager-client traces:
  # journalctl /usr/bin/security-manager-tests

Change-Id: I4af35d29a6a61d3a5a0bc4c3508bb872206a2f23
Signed-off-by: Marcin Lis <m.lis@samsung.com>