Update the build tools version.

21.0.0rc1 is now 21.0.0.

Change-Id: Ia40e8e11add013d851e8e7d4eb9e6d59a3591c96
diff --git a/templates/base/_MODULE_/build.gradle.ftl b/templates/base/_MODULE_/build.gradle.ftl
index edab7c4..50caaf2 100644
--- a/templates/base/_MODULE_/build.gradle.ftl
+++ b/templates/base/_MODULE_/build.gradle.ftl
@@ -68,7 +68,7 @@
           to always use the most current SDK as their target. -->
     compileSdkVersion ${compile_sdk}
 
-    buildToolsVersion "21.0.0rc1"
+    buildToolsVersion "21.0.0"
 
     sourceSets {
         main {