Be more restrictive in catching LDAP exceptions.

django-auth-ldap can throw exceptions, like TypeError if it's
misconfigured.  If we encounter an exception attempting to log into an
LDAP server, log it and move on (otherwise, an uncaught exception will
cause local login to fail, too).

see: #5933

awx/sso/backends.py

@@ -12,7 +12,6 @@ from django.dispatch import receiver
 from django.contrib.auth.models import User
 from django.conf import settings as django_settings
 from django.core.signals import setting_changed
-from django.core.exceptions import ImproperlyConfigured
 
 # django-auth-ldap
 from django_auth_ldap.backend import LDAPSettings as BaseLDAPSettings
@@ -90,8 +89,8 @@ class LDAPBackend(BaseLDAPBackend):
             return None
         try:
             return super(LDAPBackend, self).authenticate(username, password)
-        except ImproperlyConfigured:
-            logger.error("Unable to authenticate, LDAP is improperly configured")
+        except Exception:
+            logger.exception("Encountered an error authenticating to LDAP")
             return None
 
     def get_user(self, user_id):