BUG/MEDIUM: cli: fix "show stat resolvers" and "show tls-keys"

BUG/MEDIUM: cli: fix "show stat resolvers" and "show tls-keys"

The recent CLI reorganization managed to break these two commands
by having their parser return 1 (indicating an end of processing)
instead of 0 to indicate new calls to the io handler were needed.

Namely the faulty commits are :
  69e9644 ("REORG: cli: move show stat resolvers to dns.c")
  32af203 ("REORG: cli: move ssl CLI functions to ssl_sock.c")

The fix is trivial and there is no other loss of functionality. Thanks
to Dragan Dosen for reporting the issue and the faulty commits. The
backport is needed in 1.7.