Remove redundant namespaceAliases

Same as the actual namespace names.
Apparently translatewiki doesn't handle namespaceAliases.
Bug: 51934

Change-Id: I132dabf918311712ddf83b9ac3d4ab262c8ab6bc
(cherry picked from commit 76158dc3f630cb2b3a033f4948dc69b1114a2a1b)