Do not enforce unique package name in gradle projects.

This is needed because multiple targets use the default Android manifest
with package name "dummy.package". This problem occurs when letting
gradle process resources.

BUG=682846,webrtc:6328

Review-Url: https://codereview.chromium.org/2699663004
Cr-Original-Commit-Position: refs/heads/master@{#450976}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: b4ef9a4857c32338bc7b23e30708871b7541dec0

android/gradle/android.jinja

@@ -40,6 +40,8 @@ android {
     compileSdkVersion {{ compile_sdk_version }}
     buildToolsVersion "{{ build_tools_version }}"
     publishNonDefault true
+    // Multiple targets use the package name "dummy.package"
+    enforceUniquePackageName false
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_7