net/flower: Update to 0.10

This release includes proper support for egresses, meaning sandboxed
applications can now make outgoing network connections properly. In
addition to that, a new utility, flower_ls, can be used to extract a
list of registered servers. This is pretty useful for debugging.

Bump cloudabi-utils' revision to catch up with .proto changes.

Reviewed_by: koobs
Approved by: koobs (ports)
Differential_Revision: D12399