Close PR #10264. Don't bail directly out of passwd/chpass in my_yp_match().

Close PR #10264. Don't bail directly out of passwd/chpass in my_yp_match().
Instead, treat the inability to retrieve a record from the server as a
match failure and let things take its course.

Part of the problem here is that NIS _is_ turned on, however the master
server is actually not an NIS server: it's an NIS+ server. And the client
is bound to an NIS+ replica server that's running in YP compat mode.
The code which tries to figure out of the user is local or NIS gets
confused by this.