fetch-solana-install-init.js runs into github API rate limits

[mvines]

Because fetch-solana-install-init.js runs on Travis, we share the unauthenticated github API rate limit with all other Travis users. But the Travis job already has a github token we can use to avoid this.

Once fixed, re-enable

solminer/fetch-solana-install-init.js

Line 9 in 1641a7c

//const channel = 'github-release';