Remove unused variables in the code

This commit removes unused variables or rename variables as "expected to
be unused" by using "_" prefix.

This covers only cases where fix was easy or only one unused variable
was in a module

Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>
Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>

ipaserver/install/ldapupdate.py

@@ -848,7 +848,7 @@ class LDAPUpdate(object):
     def get_all_files(self, root, recursive=False):
         """Get all update files"""
         f = []
-        for path, subdirs, files in os.walk(root):
+        for path, _subdirs, files in os.walk(root):
             for name in files:
                 if fnmatch.fnmatch(name, "*.update"):
                     f.append(os.path.join(path, name))