authplain: Escape ':'s that appear in the pwhash string as '|'

This is mostly useful for the mediawiki password hash format (supported by dokuwiki), which uses :B:<salt>:<hash>: for its internal field format. At the moment, if you're using authplain and you set this password hash type then it breaks dokuwiki.

I realise it's not a common configuration combination, but I've been working on a mediawiki->dokuwiki converter that brings over as much metadata as practical (revisions, users, etc.) and it'd be great to be able to migrate mediawiki user passwords directly to an authplain-based install.

Shouldn't break anything, there are no hash format supported by Dokuwiki that uses '|' as an internal field delimiter.

Thanks very much for all the work on Dokuwiki, it's a great wiki tool!


Angus