Update Android build to API level 17 and SDK Tools version 21

build/android/ant/create-test-jar.js

Index: build/android/ant/create-test-jar.js
diff --git a/build/android/ant/create-test-jar.js b/build/android/ant/create-test-jar.js
index d22c00319617a09ed155a28e631e8715deff6559..d9014a39cc528a62c8c28cede3fbcd5174b7c5ed 100644
--- a/build/android/ant/create-test-jar.js
+++ b/build/android/ant/create-test-jar.js
@@ -14,7 +14,6 @@ importClass(org.apache.tools.ant.types.FileSet);
 importClass(org.apache.tools.ant.types.ZipFileSet);
 importClass(org.apache.tools.ant.taskdefs.Zip);
 
-var echo = project.createTask("echo");
 var jarTask = project.createTask("jar");
 
 // Do not allow duplicates in the jar, the default behavior of Jar task
@@ -64,7 +63,4 @@ for (var i in excludedClasses) {
 }
 
 jarTask.setExcludes(exclusionString);
-echo.setMessage("Creating test jar: " +
-                jarTask.getDestFile().getAbsolutePath());
-echo.perform();
 jarTask.perform();