3f8b4604be introduced a bug: it replaced alloc_dive_site() by the
divesite constructor. However, the latter does not generate a
UUID (for that it would have to access the dive site table).
Thus newly added dive sites had no UUID and could not be saved
properly.
Use the register_site() instead of the put() function when
adding the dive site to the core, so that the UUID is created
if needed.
This needs an audit.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
6f367c70b7