build.gradle: remove clirr plugin

The clirr plugin is disabled and not used

build.gradle

@@ -5,7 +5,6 @@ buildscript {
         maven { url 'https://dl.bintray.com/content/aalmiray/kordamp' }
     }
     dependencies {
-		classpath 'org.kordamp.gradle:clirr-gradle-plugin:0.2.2'
 		classpath "biz.aQute.bnd:biz.aQute.bnd.gradle:6.0.0"
     }
 }
@@ -450,7 +449,6 @@ subprojects {
 	apply plugin: 'maven-publish'
 	apply plugin: 'signing'
 	apply plugin: 'checkstyle'
-	apply plugin: 'org.kordamp.gradle.clirr'
 	apply plugin: 'biz.aQute.bnd.builder'
 
 	checkstyle {
@@ -559,16 +557,6 @@ subprojects {
 		sign publishing.publications.mavenJava
 	}
 
-	clirr {
-		// 2018-08-14: Disabled Clirr because
-		// - It reports an breaking change in android.jar (seems right, but there is nothing we can do about it)
-		// - Only the first smack-* projects are correctly checked,
-		//   the other ones have the output of a clirr report from a previous project
-		//   (Look at the clirr reports).
-		enabled false
-		semver false
-	}
-
 	// Work around https://github.com/gradle/gradle/issues/4046
 	task copyJavadocDocFiles(type: Copy) {
 		from('src/javadoc')
@@ -601,18 +589,6 @@ configure (androidProjects + androidBootClasspathProjects) {
 	}
 }
 
-// There is no need to ever clirr integration test projects and the
-// smack-repl project.
-configure(integrationTestProjects + project(':smack-repl')) {
-	clirr {
-		enabled false
-	}
-}
-
-// Disable clirr on omemo modules
-project(':smack-omemo').clirr.enabled = false
-project(':smack-omemo-signal').clirr.enabled = false
-
 subprojects*.jar {
 	manifest {
 		from sharedManifest
@@ -697,12 +673,6 @@ task jacocoRootReport(type: org.gradle.testing.jacoco.tasks.JacocoReport) {
 	setOnlyIf { true }
 }
 
-// Important to specify this task after the subprojects block
-task clirrRootReport(type: org.kordamp.gradle.clirr.ClirrReportTask) {
-	dependsOn = subprojects.tasks.clirr
-	reports = files((subprojects.findAll { it.clirr.enabled == true }).tasks.clirr.xmlReport)
-}
-
 task integrationTest {
 	description 'Verify correct functionality of Smack by running some integration tests.'
 	dependsOn project(':smack-integration-test').tasks.run