gplazma-nis: plugin should fail on invalid mapping

in set up like:

map      sufficient nis
map      sufficient  authzdb

nis plugin will always stop processing even if mapping is not found.

Ticket: #7946
Acked-by: Paul Millar
Target: trunk, 2.6, 2.7
Require-book: no
Require-notes: yes

modules/gplazma2-nis/src/main/java/org/dcache/gplazma/plugins/Nis.java

@@ -111,6 +111,7 @@ public void map(Set<Principal> principals) throws AuthenticationException {
                 }
             } catch (NamingException e) {
                 _log.warn("Faild to get mapping: {}", e.toString());
+                 throw new AuthenticationException("no mapping: "+ e.getMessage(), e);
             }
         }
     }