sequences: the result of an action should be pass into the next action in the sequence

[shazron]

See https://github.com/apache/openwhisk/blob/master/docs/actions.md#creating-action-sequences for the expected behaviour

From the doc:

• Parameters passed between actions in the sequence are explicit, except for default parameters.
• Parameters that are passed to the sequence action (e.g., mySequence) are only available to the first action in the sequence.
• The result of the first action in the sequence becomes the input JSON object to the second action in the sequence (and so on).
• This object does not include any of the parameters originally passed to the sequence unless the first action explicitly includes them in its result.
• Input parameters to an action are merged with the action's default parameters, with the former taking precedence and overriding any matching default parameters.

[aiojbot]

JIRA issue created: https://jira.corp.adobe.com/browse/ACNA-2966

[shazron]

Added in PR #25