Update ldap-checker.py

Changed catch all exception as suggesteed.

Signed-off-by: Cauan <cauan@users.noreply.github.com>

Author: cauan

nxc/modules/ldap-checker.py

@@ -142,7 +142,7 @@ async def run_ldap(target, credential):
                     # because LDAP server signing requirements are not enforced
             except Exception as e:
                 context.log.debug(str(e))
-                return False
+                return None
 
 
         # Run trough all our code blocks to determine LDAP signing and channel binding settings.