CI: hang (sometimes) on lerna boostrap in travis-ci

[tylerbrandt]

Several recent builds (including on master) have been hanging during lerna boostrap. With the aid of verbose logging via #130 I can see that they are actually hanging after this:

> optimizely-sdk-packages@1.0.0 postinstall /home/travis/build/optimizely/javascript-sdk
> lerna bootstrap && lerna run build
lerna verb rootPath /home/travis/build/optimizely/javascript-sdk
lerna info version 2.11.0
lerna info versioning independent
lerna info Bootstrapping 1 packages
lerna info lifecycle preinstall
lerna verb dependencyIsSatisfied bluebird false
lerna verb dependencyIsSatisfied chai false
lerna verb dependencyIsSatisfied coveralls false
lerna verb dependencyIsSatisfied eslint false
lerna verb dependencyIsSatisfied grunt false
lerna verb dependencyIsSatisfied grunt-karma false
lerna verb dependencyIsSatisfied istanbul false
lerna verb dependencyIsSatisfied json-loader false
lerna verb dependencyIsSatisfied karma false
lerna verb dependencyIsSatisfied karma-browserstack-launcher false
lerna verb dependencyIsSatisfied karma-chai false
lerna verb dependencyIsSatisfied karma-chrome-launcher false
lerna verb dependencyIsSatisfied karma-mocha false
lerna verb dependencyIsSatisfied karma-sinon false
lerna verb dependencyIsSatisfied karma-webpack false
lerna verb dependencyIsSatisfied load-grunt-tasks false
lerna verb dependencyIsSatisfied mathjs false
lerna verb dependencyIsSatisfied mocha false
lerna verb dependencyIsSatisfied mocha-lcov-reporter false
lerna verb dependencyIsSatisfied nock false
lerna verb dependencyIsSatisfied sinon false
lerna verb dependencyIsSatisfied webpack false
lerna verb dependencyIsSatisfied json-schema false
lerna verb dependencyIsSatisfied lodash false
lerna verb dependencyIsSatisfied murmurhash false
lerna verb dependencyIsSatisfied sprintf false
lerna verb dependencyIsSatisfied uuid false
lerna info Installing external dependencies
lerna verb actions 1 actions, concurrency 4

When successful the remaining lines are

lerna verb installed leaf @optimizely/optimizely-sdk
lerna info Symlinking packages and binaries
lerna info lifecycle postinstall
lerna info lifecycle prepublish
lerna info lifecycle prepare
lerna success Bootstrapped 1 packages
lerna verb rootPath /home/travis/build/optimizely/javascript-sdk
lerna info version 2.11.0
lerna info versioning independent

I guess we'll have to dig into lerna to figure out what that means.

[tylerbrandt]

After increasing the log level to "silly" I see that some builds (e.g. https://travis-ci.org/optimizely/javascript-sdk/jobs/397907347) are actually hanging on installing grunt-cli, with this being the last line:

$ npm install grunt-cli -g

[spencerwilson-optimizely]

This was at least circumvented in #129, which bypassed lerna and uninstalled grunt. Closing this since it's not ongoing anymore. Perhaps we'll encounter another flavor of it later on...