Fix no links property in flavor list response

The response in flavor list should contain a links property

Closes-Bug: #1372934
Change-Id: I8b4c67c891c930b70ef3f56931e9850e4a0b54a6
(cherry picked from commit d5403cd87cd89a63dbc5ee97f69540a5ce849639)
Merge "Fix no links property in flavor list response" into proposed/juno