gulp build fails if getGeneratorConfig doesn't find a .yo.rc file outside the project directory

[seanpk]

I think it should also work with a file in the project directory, and maybe even without one.

The impact of this is that builds don't work until the developer puts a .yo.rc file one level up from the git project where the blueoak-build gulp script works.

$ gulp build
[12:00:45] Using gulpfile ~/blueoak/blueoak-cms-psxm/gulpfile.js
[12:00:45] Starting 'build-spa'...
[12:00:45] all files 43.02 kB
[12:00:45] 'build-spa' errored after 672 ms
[12:00:45] Error: ENOENT: no such file or directory, open '../.yo-rc.json'
    at Error (native)
    at Object.fs.openSync (fs.js:549:18)
    at Object.fs.readFileSync (fs.js:397:15)
    at Object.getGeneratorConfig (/home/devin/blueoak/blueoak-cms-psxm/node_modules/blueoak-build/gulp/utils.js:120:11)
    at Object.compileSass (/home/devin/blueoak/blueoak-cms-psxm/node_modules/blueoak-build/gulp/spa/styles.js:51:30)
    at Builder.stylesNoMin [as _stylesNoMin] (/home/devin/blueoak/blueoak-cms-psxm/node_modules/blueoak-build/gulp/spa/withDebugSPABuildPrimitives.js:31:16)
    at Builder.<anonymous> (/home/devin/blueoak/blueoak-cms-psxm/node_modules/blueoak-build/gulp/spa/withDebugSPABuildPrimitives.js:52:52)
    at _fulfilled (/home/devin/blueoak/blueoak-cms-psxm/node_modules/q/q.js:854:54)
    at self.promiseDispatch.done (/home/devin/blueoak/blueoak-cms-psxm/node_modules/q/q.js:883:30)
    at Promise.promise.promiseDispatch (/home/devin/blueoak/blueoak-cms-psxm/node_modules/q/q.js:816:13)
[12:00:45] gulp-inject 6 files into app/index.scss.