Cannot use same transaction for delete and set mutations

[cyphercider]

This is an issue to track dgraph-io/dgraph-js#21, originally submitted for the js client, but which belongs to dgraph server per @pawanrawal .

@pawanrawal , this issue happens 100% of the time on my setup. One possible difference between your and my setups is that my dgraph server is actually hosted remotely, and network latency is pretty high (50-100ms). I'm not sure whether there's any link between my high latency and consistent reproduction of the issue, but FYI just in case it's significant.

[pawanrawal]

The issue is reproducible when running Dgraph in a VM. I am investigating this and will update the cause here soon.

[pawanrawal]

I have a fix for this in #2105 which will be merged soon.

[pawanrawal]

A fix has been pushed to master in 42b0167 and would be part of the nightly/next release.

[cyphercider]

Looks good! Confirmed fix on docker hub tag 'master'.