Redmine #6370: Discard call collect connection.

Instead of sending "BAD: Unspecified server refusal
(see verbose server output)" message to the call collected client
which is not having access to call collect simply refuse connection.

Message sent to the client is interpreted as a call collect queue
length and client assumes that connection is valid.
Merge pull request #1876 from pasinskim/ha

Redmine #6370: Discard call collect connection.