Revert "Creates the new x-goog-api-client header."

[stephenplusplus]

Reverts #2020

[jmuk]

Ugh, I didn't notice this. Why reverted? This means lacking the header info for non-gapic APIs.

cc: @bjwatson @lukesneeringer

[stephenplusplus]

#2020 (comment)

@jmuk - sorry, can you PR this again? Each gRPC API using GrpcService already passes in its package.json. The GrpcService class has access to it under options.packageJson.

I was suggesting we not do any code changes in packages/src/{service}/index.js, rather move them to packages/common-grpc/index.js, since it should have all the information it needs from the package.json it is sent from the extending service class.

Looking at the other PRs, I don't think you went with that style (which makes sense, if you never saw the comment), and I must have forgotten about that request, so now we're in a half-n-half state.

[jmuk]

Created #2164