Failure stops other authenticators

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Put the following in a .htaccess file:
AuthType Basic
AuthBasicProvider external file
AuthExternal pwauth
AuthUserFile /web/htpasswd
Require valid-user
2. Access a URL under that tree
3. Offer credentials of a user described in /web/htpasswd

What is the expected output? What do you see instead?
Page should load. Instead, I get back "401 Authorization Required". The
error log shows the following:
[Thu May 27 11:57:51 2010] [error] [client 128.zzz.xxx.yyy] AuthExtern
pwauth [/usr/local/bin/pwauth]: Failed (1) for user htphil
[Thu May 27 11:57:51 2010] [error] [client 128.zzz.xxx.yyy] user htphil:
authentication failure for "/test/": Password Mismatch
Apparently, mod_authn_file was never consulted

What version of the product are you using? On what operating system?
Package libapache2-mod-authnz-external version 3.1.0-1ubuntu2 on Ubuntu
8.04.4 Hardy

Please provide any additional information below.
The documentation says that mod_auth_basic handles the issue of treating
the auth[nz] modules non-authoritatively, but that doesn't quite seem to be
the case.

Original issue reported on code.google.com by [email protected] on 27 May 2010 at 5:11