ftp_domore_getsock: when passive mode, the second conn is already there

This makes the socket callback get called with the proper bitmask as
otherwise the application could be left hanging waiting for reading on
an upload connection!

Bug: http://curl.haxx.se/mail/lib-2013-08/0043.html
Reported-by: Bill Doyle
--help: fix the --sasl-ir in the help output
ftp: convert state names to a global array

... just to make them easier to print in debug ouputs while debugging.
They are still within #ifdef [debugbuild].