Check also for rules set in an environment variable QT_LOGGING_RULES.
This makes it even more convenient to set rules e.g. for just one run of an
application, without having to create a logging configuration file. It
is also more in place with the current way we enable/disable debugging
of parts of Qt via environment variables.
Change-Id: I4d05976f2b6c12bca472552ffa22345475cd01de
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Reviewed-by: Tomasz Olszak <olszak.tomasz@gmail.com>
ef43967fcd