Fixed detection of unsigned mysql column in updater

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