Bug 1570640: Ignore plugins with bad auth config

When looping through all auth to see if a user can login

behatnotneeded

Change-Id: I51693fac3c650ff529ccfc98586c50f4d185f591
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
(cherry picked from commit 4993ce1c)

htdocs/auth/lib.php

@@ -1502,7 +1502,12 @@ function login_submit(Pieform $form, $values) {
                     else {
                         continue;
                     }
-                } catch  (AuthInstanceException $e) {
+                }
+                catch  (AuthInstanceException $e) {
+                    continue;
+                }
+                catch (UninitialisedAuthException $ue) {
+                    log_info('Malformed auth instance "' . $auth->instancename . '" for institution "' . $auth->institution . '"');
                     continue;
                 }