[devstack] use the generic function to setup logging
[devstack] use the generic function to setup logging

This makes our logging setup compatible with USE_SYSTEMD, see gerrit
change I6af6d1857effaf662a9d72bd394864934eacbe70 for details.

Change-Id: I929bebde0ba50a6b9d5e6e0ab7e077b2c02a7849

pshchelo/ironic,SauloAislan/ironic,pshchelo/ironic,SauloAislan/ironic,openstack/ironic,openstack/ironic