tools: consistent .eslintrc formatting

All quotes in .eslintrc were unnecessary and inconsistently placed
across the file. Additionally, format the globals to be consistent
with the style of whitespace and sorted them alphabetically.

PR-URL: https://github.com/nodejs/node/pull/7691


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>