Description of problem:
Tasks are identified with task_id field while e.g. repos are OK with just id field for the same purpose

Version-Release number of selected component (if applicable):
pulp 2.2


Actual results:
task_id field is used to identify a task

Expected results:
id field is used to identify a task

Additional info:
An example of a response-containing task details in docs: https://pulp-dev-guide.readthedocs.org/en/pulp-2.2/integration/rest-api/repo/sync.html