STYLE: src/Admin: Update python scripts to use "is None" instead of "== None"

Rational copied from https://www.python.org/dev/peps/pep-0290/#testing-for-none

// -----------------
Since there is only one None object, equality can be tested with identity. Identity
tests are slightly faster than equality tests. Also, some object types may overload
comparison, so equality testing may be much slower.

Pattern:

if v == None  -->  if v is None:
if v != None  -->  if v is not None:
// -----------------