datapath: Change default log level

Change the default log level, so that deterministic startup/shutdown
messages are produced at said level.

Change-Id: I1ef4980dbc261aa9afc8ef8f08809c36f2e53144
Signed-off-by: Stephen Finucane <stephen.finucane@intel.com>
Reviewed-by: Kevin Traynor <kevin.traynor@intel.com>
Reviewed-by: Mark B. Kavanagh <mark.b.kavanagh@intel.com>