SSSDConfig: Fix SyntaxWarning "is not" with a literal
There is a warning with python 3.8
/usr/lib/python3.8/site-packages/SSSDConfig/ipachangeconf.py:399:
SyntaxWarning: "is not" with a literal. Did you mean "!="?
if len(sectopts) is not 0:
Reviewed-by: Pavel Březina <pbrezina@redhat.com>\