[Starlink] don't use openwrt-rc3

[Dave Taht]

It’s looking like openwrt - rc3 and rc2 are broken in a couple key ways on the wifi. For those you testing ath9k over wifi I’d recommend just reflashing with v19.07 for now. ath10k, just sit back a while.

We (teklibre) are starting up a major effort to get the wifi issues resolved and some new features in before this version of openwrt goes final. Huge thx to comcast research for the grant!

(If there is anyone in the bay area that would like a short term (paid) gig to put 60+ routers under test  our labs are in san leandro, half moon bay, and mariposa, let me know)