Updated mediawiki/extensions
Project: mediawiki/extensions/BookManagerv2  4bf31126b52feb8dd52c8f3abcfb64403991342a

Page numbers should not be required

Books that don't have scans won't have page numbers, so this
property should not be required.

Change-Id: I2955fce991b47c92db7f77d3574625c5373e924c