Sometimes, the primer URL login may fail, e.g. bad login. However,
since the only error indication may be a "Login failure"-type
message and not a true HTTP error code, the Search Appliance may not be able
to detect this and might continue walking useless (permission-denied
or "Please log in first") pages.
To help detect such a primer URL failure, a Bad Login MM Query
may be entered. If non-empty, this is a Metamorph query to run against
the HTML returned from the associated primer URL. If it matches, the
primer URL is considered a failure, and the walk is stopped for that
particular site (other Base URLs will continue).