Fix grammatical error in comment
Fix Grunt output not being silenced under Grunt v0.4.5

Grunt v0.4.5 moved grunt.log into separate ‘grunt-legacy-log’ module, see https://github.com/gruntjs/grunt/commit/014929198db0f86615a1431bb63309100b8b04b3. The original proxyquire was therefore no longer working.