since yp_bind() and yp_all() don't use open, fstat, read, socket, and other

since yp_bind() and yp_all() don't use open, fstat, read, socket, and other
rich system calls to perform YP/LDAP lookups, there is no need to access()
/var/run/ypbind.lock to "hint" to pledge that it should open up those system
calls.
ok jmatthew, miod