Disable sonar analysis for external PRs (#144)
Disable sonar analysis for external PRs (#144)

Currently, travis-ci sonarclould addon cannot support external PRs.
If you do sonar analysis for all builds, the external PR build will
run sonar analysis without sonarcloud addon. And it will conduct:

```
    [ERROR] SonarQube server [https://localhost:9000] can not be reached
```
Make this quick fix to disable sonar analysis for external PRs.

Known related issue: travis-ci/travis-ci#8379
codecentric/jbehave-junit-runner,valfirst/jbehave-junit-runner