Gradle plugin: unable to build project in multi flavor environment with gradle 0.11+

#KT-5348 Fixed
(cherry picked from commit 09e8d0d)

Author: NataliaUkhorskaya

libraries/tools/kotlin-gradle-plugin-core/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPlugin.kt

@@ -234,8 +234,8 @@ open class KotlinAndroidPlugin [Inject] (val scriptHandler: ScriptHandler): Plug
                 javaSourceList.add(Callable<File?>{ variant.getRenderscriptCompile().getSourceOutputDir() })
 
                 if (variant is ApkVariant) {
-                    for (flavour in variant.getProductFlavors().iterator()) {
-                       val flavourSourceSetName = buildTypeSourceSetName + flavour.getName()
+                    for (flavourName in AndroidGradleWrapper.getProductFlavorsNames(variant)) {
+                       val flavourSourceSetName = buildTypeSourceSetName + flavourName
                         val flavourSourceSet : AndroidSourceSet? = sourceSets.findByName(flavourSourceSetName)
                         if (flavourSourceSet != null) {
                             javaSourceList.add(AndroidGradleWrapper.getJavaSrcDirs(flavourSourceSet))

libraries/tools/kotlin-gradle-plugin-core/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/android/AndroidGradleWrapper.groovy

@@ -1,6 +1,7 @@
 package org.jetbrains.kotlin.gradle.plugin.android
 
 import com.android.build.gradle.BasePlugin
+import com.android.build.gradle.api.ApkVariant
 import org.gradle.api.tasks.util.PatternFilterable
 import org.jetbrains.annotations.NotNull
 
@@ -39,4 +40,9 @@ class AndroidGradleWrapper {
   static def Set<File> getJavaSrcDirs(Object androidSourceSet) {
     return androidSourceSet.getJava().getSrcDirs()
   }
+
+  @NotNull
+  static def List<String> getProductFlavorsNames(ApkVariant variant) {
+      return variant.getProductFlavors().iterator().collect { it.getName() }
+  }
 }