compositor: Fix incorrect use of bool options

WESTON_OPTION_BOOLEAN takes a pointer to an int as an argument, but
there were several cases of being passed a pointer to a bool instead.
This changes it to use a local int instead, and then write that value to
the bool.

Signed-off-by: Scott Anderson <scott.anderson@collabora.com>
(cherry picked from commit 2edbcbd9)