1. After a successful delivery, the message log file was being fclosed twice;
some operating systems' C libraries just ignore the second fclose, but others
crashed; this caused -J files to be left lying about.
2. The "contains" operation in filter files was failing to find matches when
the initial character of the searched-for string was duplicated in the subject
string, e.g. searching for "[Boston]" in "[[Boston] ..." failed. The bug was in
the "strstric()" function, which would also have affected -R and -S operations.
