servo: the --android flag is now needed for the package command

Source-Repo: https://github.com/servo/servo
Source-Revision: 1cba3b3e9835fffbae91ab9dac76ed1f75bcf5c7

servo/README.md

@@ -151,7 +151,7 @@ export ANDROID_TOOLCHAIN="/path/to/toolchain"
 export PATH="$PATH:/path/to/toolchain/bin"
 
 ./mach build --release --android
-./mach package --release
+./mach package --release --android
 ```
 
 Rather than setting the `ANDROID_*` environment variables every time, you can