After API 17 / RTL support was released, I added the following to my manifest
android:supportsRtl="true"
which caused Lint to rightfull
You're right about the root cause of the issue - Samsung defined a custom attribute for the id reserved for paddingStart or paddingEnd.
The way I by-passed this was to extract the padding properties and put them into a style. So instead of having different layouts for SDK<17 and SDK>=17, I have different styles for them (with paddingLeft&Right in values and paddingStart&End in values-v17).
This way, Lint will stop complaining about it.