Fixed detection of unsigned mysql column in updater
MediaWiki running with an old mysql or php without mysqli cannot
use the newly added flags property of Database::fieldInfo.
For backward compatibility add the missing properties using the flags
property to the result of Database::fieldInfo.
Added missing unsigned, numeric, blob and zerofill properties to the
MysqlField using flags in mysqli.
The missing fields in mysqli are taken from
http://php.net/manual/en/function.mysql-fetch-field.php
Follow-Up: I641dc1fad0a5bb14815f55e0357243a562fd672b
Change-Id: I1da904df72f8af7725fc7ff94121ef85b18a36f8