XMPP parser errors if not given a password

[csmith]

The XMPP parser fails with a NPE if you connect to a URL without a password included, e.g.:

xmpps://user%23domain@talk.google.com/

It should instead try to login without a password, and if that fails return the appropriate error to the core.

java.lang.ArrayIndexOutOfBoundsException: 1 
com.dmdirc.addons.parser_xmpp.XmppParser.run(XmppParser.java:447) 
java.lang.Thread.run(Thread.java:619)