Node: npm bump, devel killed, npm update change.

Okay, this is part 1 of what will likely become a host of wider changes
I propose on Node to tackle the issues discussed in
[#31777](https://github.com/Homebrew/homebrew/issues/31777).

Part 1: I’ve killed the devel build. It hasn’t been updated since May,
and Node haven’t expressed any sort of haste in issuing even a new
minor bump to the devel build that fixes the rather large [OpenSSL
vulnerabilities](https://github.com/joyent/node/tree/v0.11.13-release/de
ps/openssl/openssl) in 0.11.13. At this point, my feeling is that it’s
dangerously irresponsible to leave the devel build present given those
vulnerabilities, and I’d like to see us scrap it until we see some
movement on patching those issues. This issue is open with Node
[here](https://github.com/joyent/node/issues/8000) but remains largely
ignored and dormant.

Second change: Bumps the npm version that we ship back to the latest
stable release. A minor thing, but an early step towards fixing some of
the bigger npm problems.

Third change: Changes the way we handle npm updates post-install to
specifically target the latest stable release. Our current ``` npm
update npm -g ``` has been habitually dumping people onto the alpha &
beta builds for npm, and this solution (according to the npm team)
should solve that problem permanently. Having done local testing with
this, It does indeed seem to do the job.

These are largely minor fixes to patch things over in a stable, solid
fashion till I can work out ways to avoid the Node issues we’ve been
encountering so rampantly lately.
node: update 0.10.31 bottle.