Fix delete scroll issue because of long scroll id

[merajblueshift]

We will now pass scroll id in the body rather than URL because scrollIds can be long and may result in an error if passed in URL

Tested Following the change with the following test cases
ES1 Account:

1. Clearing scroll prematurely.
2. Clearing scroll after finishing the results.
3. Try reading results again after clearing scroll (Should result in 404 Scroll not found)

ES7 Account:

1. Clearing scroll prematurely
2. Clearing scroll after finishing the results.
3. Try reading results again after clearing scroll (Should result in 404 Scroll not found)

Verified on the side of the orbit whether the proper scroll id was decoded and the response of ES for the clear scroll operation from orbits.