[ChangeLog][QtCore][QLoggingCategory] Fixed behavior of default
severity passed to constructor or Q_LOGGING_CATEGORY with regards to
QtInfoMsg, which was previously treated as being more severe than
QtFatalMsg.
This is because the code was using the numeric value of QtMsgType as a
proxy for severity (via the <= operator), but the value of QtInfoMsg is
greater than QtFatalMsg. Instead, the severity ordering must be dealt
with explicitly.
Change-Id: I5f178afc735221b00cb67c2cea4fa964bd9079ce
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
8fdd1e3867