Remove the assemble task from projects not published (elastic/x-pack-elasticsearch#1721)

Removes the `assemble` task from projects that aren't published
to speed up `gradle assemble` so the unified release can call it.

Original commit: elastic/x-pack-elasticsearch@43dfcc15f3

plugin/bwc/build.gradle

@@ -31,6 +31,7 @@ subprojects {
   }
   if (enabled) {
     apply plugin: 'distribution'
+    tasks.remove(assemble)
 
     def (String major, String minor, String bugfix) = bwcVersion.split('\\.')
     def (String currentMajor, String currentMinor, String currentBugfix) = version.split('\\.')

qa/build.gradle

@@ -0,0 +1,11 @@
+
+/* Remove assemble on all qa projects because we don't need to publish
+ * artifacts for them. */
+gradle.projectsEvaluated {
+  subprojects {
+    Task assemble = project.tasks.findByName('assemble')
+    if (assemble) {
+      project.tasks.remove(assemble)
+    }
+  }
+}