daemon.man is meant to have a heading above it, but in a few manpages its
text was running directly into the previous documentation because this had
been overlooked.

By adding .PP to daemon.man, we make this problem less severe if the
heading is similarly omitted in future manpages, since at least it will
then have its own paragraph instead of running into the previous one.

Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Andy Zhou <azhou@ovn.org>