Transaction with amount 0 on http bridge fails with error HTTP 500

[piotr-iohk]

Release	Operating System	Cause
next	Linux	Code v Configuration v Environment v Human v Unknown

Context

The transaction with 0 amount on Byron node should fail more gracefully than HTTP 500. cf #335 (comment)

Steps to Reproduce

Run transaction with 0 amount from API or CLI.

Expected behavior

There should be an error (perhaps HTTP 400 or 403 on the API) and a graceful error message about 0 amount transaction not being supported on Byron node.

Actual behavior

HTTP 500

That's embarassing. It looks like I've created an invalid transaction that could
not be parsed by the node. Here's an error message that may help with 
debugging: Transaction failed verification: output with no credited value

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Resolution Plan

PR

Number	Base
#445	master

QA

• Added a new error branch when creating transaction, now triggered from the http-bridge and tested via an integration test (see TRANS_CREATE_09)

[piotr-iohk]

Looking good. Just added few more scenarios in #458