Add "cancel_timeout" parameter

[lowellausen]

We have faced the need for variable timeout values when waiting for a task to cancel.

For example: if you have a record video task that compresses a video and saves when you press cancel. It can take several seconds to do that, and, with the current implementation, the wait for cancel will timeout and the task will succeed; although the cancelling keeps going on and the task result will eventually be sent.

Changes:

• Removed the currently hard-coded 5 seconds timeout when waiting for a task to be cancelled
• Added a new parameter to make that timeout variable
  • The default value is still the same 5 seconds as before
• Removed another 5 seconds timeout that was hard-coded on the task registrator, that was simply overwriting the previously mentioned hard-coded timeout
• Had to change a test case:
  • Added the new parameter to one of the tasks being created on the integration tests
  • Added cancel_timeout of 1.5 seconds to it
  • Changed the test that creates a task that should take longer than the allowed timeout. Has to be 2 seconds now (the run_time_secs has to be an int due to its hacky nature)

[jonipol]

A small cleanup suggestions. Otherwise pretty straight forward change. LGTM!

[Jannkar]

Looks good! Nice to have this value parameterized. Couple of the tests seem to be failing after the new changes.

[lowellausen]

Looks good! Nice to have this value parameterized. Couple of the tests seem to be failing after the new changes.

Took me a while to come back to this, but fixed the tests now!

[Jannkar]

Sorry, didn't have time to recheck the changes until now. Looks good!