Don't read SSL client data before DNS resolver is finished

Fix the cb_clientserver_ssl() callback function to not read in and store SSL
encrypted client data before the asynchronous DNS resolver sub-process has
finished: This could have resulted in discarding the resolved client hostname
and IDENT reply afterwards, because in some situations (timing dependent) the
NICK and USER commands could have already been read in from the client,
stored in the buffer, and been processed.

Thanks to Julian Brost for reporting the issue and testing, and to Federico
G. Schwindt <fgsch@lodoss.net> for helping to debug it!

(cherry picked from commit b4393277ea1cc67bc8433fcbeded3fc2186f5c54)