core: logging: prefix all logs with 'otopi.'
core: logging: prefix all logs with 'otopi.'

This is needed so that external implementations will use the same
log hierarchy.

Change-Id: I46329f3e85eafeb01e3234dfc177168fb487c2b4
Signed-off-by: Alon Bar-Lev <2e3ceb4d37adc6ae3ccc00d3646e0e0a036ace03@redhat.com>

alonbl/otopi,alonbl/otopi,alonbl/otopi