Fix jacoco build error

Issue gh-95

core/spring-security-core2.gradle

@@ -8,3 +8,7 @@ dependencies {
 	testCompile 'org.assertj:assertj-core'
 	testCompile 'org.mockito:mockito-core'
 }
+
+jacoco {
+	toolVersion = '0.8.5'
+}

crypto/spring-security-crypto2.gradle

@@ -9,3 +9,7 @@ dependencies {
 	testCompile 'org.assertj:assertj-core'
 	testCompile 'org.mockito:mockito-core'
 }
+
+jacoco {
+	toolVersion = '0.8.5'
+}

jose/spring-security-oauth2-jose2.gradle

@@ -12,3 +12,7 @@ dependencies {
 	testCompile 'org.assertj:assertj-core'
 	testCompile 'org.mockito:mockito-core'
 }
+
+jacoco {
+	toolVersion = '0.8.5'
+}