rfe14670: Make python tutorial default to the rootcatalog
rfe14670: Make python tutorial default to the rootcatalog

Change the default AG_CATALOG to the rootcatalog, since
`default' AG installations do not have a python-catalog
defined.

Tests added for:       none
make test-suite run?   no
Documentation changes? yes, rfe14669

releases notes: rfe14669

Change-Id: I09b501a29a56fa536b4c1afecc099906577d4d39
Reviewed-on: https://gerrit.franz.com:9080/6599
Reviewed-by: Mikel Bancroft <ca199d392fdede43b8830d4b3db1414754d5a2f7@franz.com>
Reviewed-by: Ahmon Dancy <8f7d8ce2c6797410ae95fecd4c30801ee9f760ac@franz.com>
Tested-by: Ahmon Dancy <8f7d8ce2c6797410ae95fecd4c30801ee9f760ac@franz.com>

franzinc/agraph-python,franzinc/agraph-python,franzinc/agraph-python,franzinc/agraph-python