npm doesn't seem to use snap proxy

I belive that this is addressed by
 https://github.com/snapcore/snapcraft/pull/762

My current theory is that proxy from environment is properly respected but just that node plugin is doing its download in the build phase. the pull request there changes it to do it during the pull phase (and then utilize cache in build).

https://code.launchpad.net/~rocket.chat.buildmaster/+snap/rocket.chat.develop/+build/4911 is an example of this still failing after Scott's fix.

npm ERR! network tunneling socket could not be established, cause=write EPROTO 139638736619328:error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol:../deps/openssl/openssl/ssl/s23_clnt.c:794:

looks suspicious here. Where's "unknown protocol" coming from?

Maybe this is indeed needed https://github.com/snapcore/snapcraft/pull/738
Or a launchpad workaround.

So i'm seeing a couple of articles from about a year ago still acting like npm_config_https_proxy / npm_config_proxy are still needed for npm.

Example of one I found:
http://intenseagile.com/npm-behind-proxy

Here's an issue on the npm repo:
https://github.com/npm/npm/issues/2866

looks like they still haven't fully figured things out them selves? A couple comments on that ticket indicate a work around is the same as presented in the PR.

Not ideal fix probably.. But looks to be necessary?

I think it's sufficient to fix our https_proxy setting to be http:// rather than https://.