Fixed coveralls build, see spotbugs#308

The coverage was executed also on test code, and tests contained
duplicated classes (which is OK), but this shoked jacoco build. We
should not run coverage on test code, it does not make any sense.

build.gradle

@@ -43,7 +43,11 @@ task jacocoRootReport(type: JacocoReport) {
 
   executionData project(':spotbugs').file('build/jacoco/test.exec')
   sourceDirectories = files(subprojects.sourceSets.main.allSource.srcDirs)
-  classDirectories = files(subprojects.sourceSets.main.output)
+
+  // Only enable class directories related to non-test project
+  classDirectories = files(subprojects.sourceSets.main.output).filter {
+    !it.toString().contains("test") && !it.toString().contains("Test") && !it.toString().contains("junit")
+  }
 
   reports {
     xml.enabled = true

gradle/jacoco.gradle

@@ -1,7 +1,7 @@
 apply plugin: "jacoco"
 
 jacoco {
-  toolVersion = "0.7.8"
+  toolVersion = "0.7.9"
 }
 
 jacocoTestReport {