Bug 11537: (follow-up) mock C4::Context::preference

This avoids turning t/Log.t into one that requires a valid
session context.

To test:

[1] Run the following and verify that the test passes.

unset KOHA_CONF
prove -v t/Log.t

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Bug 11503: [Follow-up] fix another typo

There is still a typo left to fix which I didn't catch because I was
doing a spell-check and didn't double-check the bug report:

Van der Griten -> Van der Grinten

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>