sonar.ts.tslint.path config always needed, even when re-using tslint output

When re-using a tslint output generated by the build process, sonar.ts.tslint.path still needs to be configured and pointing to an existing file. 
If that is not the case, the plugin provides the message "[WARNING] Path to tslint not defined or not found. Skipping tslint analysis." and stops the analysis.