Fixed LampState parsing.

In ParseLampState, ParseValue<> was repeatedly called inside one expression.
Correct behaviour of the function relied on the calls being executed left-to-
right, which is not guaranteed by C++. Changed to make the calls explicitly
in the right order.

Change-Id: Ia759766f3f7ab7b58332d202555cf51787a6d3b8
Signed-off-by: Andrzej Szombierski <qq@kuku.eu.org>