Fix multiple metacontact requests at startup

_continue_connection_request_privacy() should only trigger
once after we received the discoinfo on the hostname.

We do a discoinfo on all items that the server offers,
_continue_connection_request_privacy() was triggered on every received
discoinfo again, hence requesting metacontacts and delimiters again.

also _continue_connection_request_privacy() was called on every
discoinfo error, instead of only on a hostname discoinfo error.

This bug is only triggered if the server doesnt support privacy rules.