Include command in error event

[ajoaoff]

Fixes #94

:bookmark_tabs: Description of the Change

The flow mod error event now includes the command (add or delete) sent to the switch. This will help other NApps listening to the event to decide what to do based on the command

:computer: Verification Process

Unit tests were modified to reflect the changes in the event

:page_facing_up: Release Notes

• Command (add or delete) is now part of the event when flow mod fails.

[ajoaoff]

My mistake. It is delete, not remove.