site: Always advertise all capabilities

site: Always advertise all capabilities

The first version that can cope with this is 0.3.0 which is already
quite old (September 2013).  All older versions are quite badly
broken: eg, they use the serpent256-cbc transform.

This is the next phase in eventually getting rid of the distinction
between early and late capabilities.  When every running version of
secnet has this commit, we can declare every capability early since
every secnet will always advertise them early.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>