bmed: Avoid failing to bind() due to "Address already in use"

bmed: Avoid failing to bind() due to "Address already in use"

If the previous invocation of the process happened just a while ago
(eg. the daemon was restarted), the listening socket might still be in
TIME_WAIT state, which prevents registering a new listening socket to
the port. This can be avoided by using the SO_REUSEADDR option which
instructs bind() call to bind to the port anyway.

Signed-off-by: Timo Kokkonen <timo.t.kokkonen@iki.fi>