Extras: Change TYPE of braces around single statement

Change the TYPE of the "braces {} are not necessary for single statement
blocks" warning from BRACES to BRACES_SINGLE_STMT in order to correctly
ignore this particular warning and continue to warn for other BRACES
warnings.

Signed-off-by: Christian Babeux <christian.babeux@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>