Obsolete Simple English projects are not an alias

The Simple English Wikibooks and Wikiquote were closed, and their
content was not systematically migrated to the normal English project.
As such, using 'simple' as an obsolete alias for 'en' is not correct.

Change-Id: Idd1b0fdf27b81d3d3a061027543c75cabc77cde0
Merge "Obsolete Simple English projects are not an alias"