Add yet another 4 bytes of capability flags for new MariaDB functionality:
- from server->client in handshake packet V1
- client parse version info to be sure that it is MariaDB server
- server put flags in last 4 of unused 10 (bytes 14-17)
- from client->server (only if server mariadb and version is >= 10.2) V1
- client sets 'client_long_password=0' and 'client_protocol_41=1'
- puts flag in last 4 of 23 unused
Move CLIENT_PROGRESS flag to the new flag space.