Defer initializing the API in dogtag-ipa-ca-renew-agent-submit
Wait until we know a supported operation is being called
(SUBMIT and POLL) before initializing the API, which can be
an expensive operation.
https://bugzilla.redhat.com/show_bug.cgi?id=1656519
Reviewed-By: Fraser Tweedale <ftweedal@redhat.com>