Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  f1a6cebb19a12d7c9a0af613f015c14d63c4066c

Use hasOwnProperty() instead of !== undefined

This prevents conflicts with predefined object methods.

Change-Id: I3804d3c7c1439d0818a01c03b5fb5b0328c953a4