child_process.spawn fails on Windows given a space in both the command and an argument

Repro: https://gist.github.com/smrq/f028b22bc748af9e68a7 The gist of this issue is that on Windows, `child_process.spawn` handles the command incorrectly when both it and one of its arguments contains a space. So, this works fine: ``` js var spawn = require('child_process').spawn; spawn('nospaces.cmd', ['arg with spaces']); spawn('command with spaces.cmd', ['nospaces']); ``` But this yields `'command' is not recognized as an internal or external command, operable program or batch file.`: ``` js spawn('command with spaces.cmd', ['arg with spaces']); ``` Tested on Windows 7 with node 0.12.7.