charon-tkm: Add missing comma to enum

Add missing comma to tkm_context_kind_names enum definition.
charon-tkm: Properly reset CC context in listener

Make sure that the acquired CC context is correctly reset and the
associated ID released in the authorize() function of the TKM bus
listener.
testing: Update tkm/multiple-clients/evaltest.dat

Since the CC context is now properly reset in the bus listener plugin,
the second connection from host dave re-uses the first CC ID. Adjust
the expect string on gateway sun accordingly.