In current implementation few issues were fixed making passive
connection scheme more reliable:
* If it's IPV4, try PASV first, as some servers and ALGs get
confused by EPSV, and only then EPSV as a fallback
* When trying PASV or EPSV, actually try to connect to the provided
port and if the connection fails, still try the next method
* PASV and EPSV response parsing code was factored out in separate
routines for clarity
Signed-off-by: Yury V. Zaytsev <yury@shurup.com>
ada1848268