Bug 1366644 - Pre: Print Android sdkmanager package listing. r=maliu

This is simply diagnostic; it's nice to see what the versions of the
Android packages installed are, like:

Installed packages:
  Path                              | Version      | Description                       | Location
  -------                           | -------      | -------                           | -------
<snip>
  platforms;android-23              | 3            | Android SDK Platform 23           | platforms/android-23/
  tools                             | 26.0.1       | Android SDK Tools 26.0.1          | tools/

This is really useful because it's not possible to pin most packages
to specific versions; that is, we can only install latest "tools", not
"tools;26.0.1".

MozReview-Commit-ID: HgZLGCAObEs

taskcluster/scripts/misc/repack-android-sdk-linux.sh

@@ -13,6 +13,10 @@ mkdir -p $HOME/artifacts $UPLOAD_DIR
 cd /builds/worker/workspace/build/src
 ./mach python python/mozboot/mozboot/android.py --artifact-mode --no-interactive
 
+# It's nice to have the build logs include the state of the world upon
+# completion.
+/builds/worker/.mozbuild/android-sdk-linux/tools/bin/sdkmanager --list
+
 tar cf - -C /builds/worker/.mozbuild android-sdk-linux | xz > $UPLOAD_DIR/android-sdk-linux.tar.xz
 
 ls -al $UPLOAD_DIR