Fix transaction handling in providers

Fix transaction handling in providers

When a provider redirects to the login code, it must retain 'ownership'
of the transaction, otherwise the login code will wipe the transaction
data as sson as the authentication is completed but before the provider
has completed its part of the transaction.
Make sure the transaction code retrieves the 'owner' from the data for
pre-existing transactions.

Signed-off-by: Simo Sorce <simo@redhat.com>
Reviewed-by: Patrick Uiterwijk <puiterwijk@redhat.com>