RFR: 8031435: Ftp download does not work properly for ftp user without password

[Rob McKenna]

Hi folks,

Very simple fix to allow FtpURLConnection connect without a password in 
the url. (i.e. ftp://user@server/ as opposed to the current 
ftp://user:@server)

http://cr.openjdk.java.net/~robm/8031435/webrev.01/

     -Rob