stunnel: install fake cert mentioned in caveats.
stunnel: update 5.07b2 bottle.

Closes #33775.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
libcppa 0.11

libcppa has been renamed to actor-framework or libcaf (pkg name) since 0.10,
but we still use the old name for the consistency with the old one.
libcppa: update 0.11.0 bottle.