Fix EventLogging schema declarations

$wgEventLoggingSchemas declarations were moved into the 
ResourceLoaderRegisterModules hook in 1.24wmf20, which caused EL
to stop working (probably it reads the variable before that hook
gets called). This change moves them back.

Change-Id: I07ffd6e9b35e173c6fa3ac4cef784de5a726386a
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/894
(cherry picked from commit d8ab4a3378e966cf666ad1bb28bc1cd4d73f69a8)