BUG/MINOR: acl: correctly consider boolean fetches when doing casts

Commit 5adeda1 (acl: add option -m to change the pattern matching method)
was not completely correct with regards to boolean fetches. It only used
the sample type to determine if the test had to be performed as a boolean
instead of relying on the match function. Due to this, a test such as the
following would not correctly match as the pattern would be ignored :

    acl srv_down srv_is_up(s2) -m int 0

No backport is needed as this was merged first in 1.5-dev18.
diff --git a/src/acl.c b/src/acl.c
index 26c0ac8..664ef5c 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -1750,7 +1750,7 @@
 					continue;
 				}
 
-				if (smp.type == SMP_T_BOOL) {
+				if (expr->match == acl_match_nothing) {
 					if (smp.data.uint)
 						acl_res |= ACL_PAT_PASS;
 					else