message.el (message-expand-name): Don't trust the return value of bbdb-complete-name.

message.el (message-expand-name): Don't trust the return value of bbdb-complete-name.
 (message-check-news-header-syntax): Remove unused var `start'.
 (message-idna-to-ascii-rhs-1): Remove unused vars `rhs' and `address'.
 (message-inhibit-body-encoding): Move to before first use.
 (mail-abbrev-mode-regexp, Expires, User-Agent, Lines, Distribution)
 (To, References, In-Reply-To, Newsgroups, Subject, Path, From)
 (Organization, Message-ID, Date, mh-previous-window-config):
 Defvar the vars using dynamic scoping.