res_ari: Fix some off-nominal paths just dropping the HTTP connection.

* Removed some incorrect newlines on ast_http_error() messages in
manager.c.

* Removed an incorrect newline in res_ari_channels.c.

Addendum to ASTERISK-23552
........

Merged revisions 417932 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@417933 65c4cc65-6c06-0410-ace0-fbb531ad65f3