Enable 'No action' (simple decicion) motions in subdomains

[area]

The original implementation in #1071 failed to consider we would want to make such NO_ACTION motions in subdomains. In createMotion, ColonyRoles(target).getCapabilityRoles(action) | ROOT_ROLES == ROOT_ROLES would evaluate to true, as the colony does not know a function with the signature 0x12345678, and so would return 0x0 ffrom getCapabilityRoles.

As a result, attempting to create such a motion in anything other than the root domain would fail.

This PR fixes the issue by adding a special case on creation for such a motion, and adds a test demonstrating the issues is resolved. I have asserted that such a motion has an 'effect' on the domain the vote is taking place in.