Fix NoSuchMethodException in getReportsDirectory

After building the "sonar scala" plugin from master, and installing in Sonar v4.1.1, I received the following error when running mvn sonar:sonar

java.lang.NoSuchMethodError: org.sonar.plugins.surefire.api.SurefireUtils.getReportsDirectory(Lorg/sonar/api/resources/Project;)Ljava/io/File;
at org.sonar.plugins.scala.surefire.SurefireSensor.analyse(SurefireSensor.java:51)
at org.sonar.batch.phases.SensorsExecutor.execute(SensorsExecutor.java:72)

The "objective-c plugin" hit the same issue which they fixed here:
https://github.com/drewcrawford/sonar-objective-c/commit/ec68e769aef8675eb3f5a748d853741461c5d9c6

I modified their solution to use getFileSystem().resolvePath so that Maven multi-module builds will also work.

src/main/java/org/sonar/plugins/scala/surefire/SurefireSensor.java

@@ -21,6 +21,7 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.sonar.api.CoreProperties;
 import org.sonar.api.batch.CoverageExtension;
 import org.sonar.api.batch.DependsUpon;
 import org.sonar.api.batch.Sensor;
@@ -48,8 +49,9 @@ public boolean shouldExecuteOnProject(Project project) {
     }
 
     public void analyse(Project project, SensorContext context) {
-        File dir = SurefireUtils.getReportsDirectory(project);
-        collect(project, context, dir);
+        String path = (String) project.getProperty(CoreProperties.SUREFIRE_REPORTS_PATH_PROPERTY);
+        File pathFile = project.getFileSystem().resolvePath(path);
+        collect(project, context, pathFile);
     }
 
     protected void collect(Project project, SensorContext context, File reportsDir) {