data: Fix httpd configuration with require_password=never

The AuthType, AuthName, AuthDigestDomain, AuthDigestProvider,
AuthUserFile and AuthGroupFile directives should be in an
<IfDefine> section, executed only when password authentication
is configured, otherwise we get this error:
"AuthType configured with no corresponding authorization directives"

Thanks to scorpy_sk@yahoo.com and Arno Töll.