Revert "Add android-L target to the buildserver"

This reverts commit 7809ef419f.

android-L is a preview, we want to add android-20 when it comes out.

buildserver/cookbooks/android-sdk/recipes/default.rb

@@ -66,7 +66,7 @@ end
 
 %w{android-3 android-4 android-5 android-6 android-7 android-8 android-9
    android-10 android-11 android-12 android-13 android-14 android-15
-   android-16 android-17 android-18 android-19 android-20 android-L
+   android-16 android-17 android-18 android-19 android-20
    extra-android-support extra-android-m2repository}.each do |sdk|
 
   script "add_sdk_#{sdk}" do