Fix: use golang:alpine as base and re-enable CGO for revad

[SamuAlfageme]

No description provided.

[michielbdejong]

I got an error standard_init_linux.go:219: exec user process caused: no such file or directory while trying this for the first time. Will investigate where that could have come from, because it doesn't seem related to the change, I think.

Ah wait that is the same error as in #1765. Does this PR aim to fix #1765, actually?

[SamuAlfageme]

@michielbdejong how were you starting the revad container? #1765 should have been fixed with #1766 for the reva cli client.

This PR replaces scratch with golang/alpine as base for running the revad binary, since as @IljaN pointed out in #1766 (comment), we're not able to disable CGO for some dependencies. e.g.

2021-06-15 15:39:31.314 ERR go/src/github/cs3org/reva/cmd/revad/runtime/runtime.go:197 > 
  error starting the http server error=
    "http service dataprovider could not be started,: localfs: 
      error initializing db: localfs: 
      error preparing statement: 
        Binary was compiled with 'CGO_ENABLED=0', go-sqlite3 requires cgo to work. 
        This is a stub" 
  pid=1

[michielbdejong]

@SamuAlfageme thanks, I'll have a look!

[michielbdejong]

OK, it's working for me too now. I was getting that error because I was using ubuntu as the runtime image for revad. I switched to golang:alpine now and that works! All good! 👍