fix heroku reprompting for app name when not found

[ruddell]

When a Heroku app is not found, the user is prompted to re-run jhipster heroku to create a new deployment. To enable regenerating the Heroku deployment, the herokuAppName config is set to null.

The config is later saved with the value of this.herokuAppName in the saveConfig step, rather than null.

This commit fixes the behavior. Now, when an app is not found, re-running jhipster heroku prompts you to create a new deployment. It also skips other steps when finding the app fails (such as editing the pom.xml).

Related to this StackOverflow question

• All continuous integration tests are green
• Tests are added where necessary
• jhipster-online was updated if necessary
• Documentation is added/updated where necessary
• Coding Rules & Commit Guidelines as per our CONTRIBUTING.md document are followed

[mshima]

An alternative for those abort conditions, is to use cancelCancellableTasks().
Like:

generator-jhipster/generators/languages/index.js

Line 152 in a9c9a76

this.cancelCancellableTasks();

Current PR seems to fix the problem.

[ruddell]

Will create a new PR for cancelCancellableTasks everywhere