Mesh can be WiFi and Ethernet (OLSR)...although I think the OP's question was specific to "wireless mesh technologies" - anyways, your diagram doesn't need a mesh scenario, unless you're considering:
- one wire fails between the OpenWrt and an AP
- or devices on either AP may need to be isolated; but send traffic to each other (in which case, the wire would likely be faster)
It's overkill, but it is possible. Just note, the APs will become routers in this scenario and would not "roam" like a "wireless mesh technology" - OLSR is more of a routing mesh solution.