Build docker images for beta versions.
Build docker images for beta versions.

This should do two things:
* re-enable acceptance tests for tagged commits: fixes #5698
* push docker image with version=git tag

sunya123/cockroach,glycerine/cockroach,petermattis/cockroach,maxlang/cockroach,arjun4084346/cockroach,cockroachdb/cockroach,glycerine/cockroach,vivekmenezes/cockroach,veteranlu/cockroach,vaibhavarora/cockroach,vivekmenezes/cockroach,maxlang/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,arjun4084346/cockroach,arjun4084346/cockroach,maxlang/cockroach,veteranlu/cockroach,maxlang/cockroach,sunya123/cockroach,vivekmenezes/cockroach,veteranlu/cockroach,vaibhavarora/cockroach,glycerine/cockroach,bg451/cockroach,cockroachdb/cockroach,bg451/cockroach,maxlang/cockroach,vivekmenezes/cockroach,maxlang/cockroach,petermattis/cockroach,sunya123/cockroach,cockroachdb/cockroach,sunya123/cockroach,arjun4084346/cockroach,veteranlu/cockroach,paperstreet/cockroach,petermattis/cockroach,bg451/cockroach,sunya123/cockroach,petermattis/cockroach,vivekmenezes/cockroach,maxlang/cockroach,paperstreet/cockroach,petermattis/cockroach,sunya123/cockroach,paperstreet/cockroach,glycerine/cockroach,arjun4084346/cockroach,glycerine/cockroach,veteranlu/cockroach,cockroachdb/cockroach,glycerine/cockroach,cockroachdb/cockroach,petermattis/cockroach,paperstreet/cockroach,bg451/cockroach,arjun4084346/cockroach,veteranlu/cockroach,veteranlu/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,cockroachdb/cockroach,cockroachdb/cockroach,vaibhavarora/cockroach,sunya123/cockroach,glycerine/cockroach,maxlang/cockroach,bg451/cockroach,vivekmenezes/cockroach,sunya123/cockroach,vivekmenezes/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,petermattis/cockroach,vivekmenezes/cockroach,paperstreet/cockroach,bg451/cockroach,vaibhavarora/cockroach,glycerine/cockroach,arjun4084346/cockroach,petermattis/cockroach,veteranlu/cockroach,bg451/cockroach,cockroachdb/cockroach,arjun4084346/cockroach