(fix) add option for e2eTestFramework

By creating a separate key for e2eTestFramework a breaking change is
avoided. Previously, if the user had selected Mocha for unit testing,
Mocha would be used for the e2e tests being generated, but the Protractor
config would have been for Jasmine. Now, if the key doesn't exist, then
the generator uses Jasmine for generating e2e tests.