render: don't free blur_kerns_cache when it's not used

blur_kernel_count could be none zero when user set a blur kernel but
didn't enable blur. In that case deinit_render will try to free
elements of blur_kerns_cache, causing a segfault because
blur_kerns_cache is never allocated.

Fixes #209

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

Author: yshui

src/render.c

@@ -1198,10 +1198,12 @@ void deinit_render(session_t *ps) {
 	}
 #endif
 
-	for (int i = 0; i < ps->o.blur_kernel_count; i++) {
-		free(ps->blur_kerns_cache[i]);
+	if (ps->o.blur_method != BLUR_METHOD_NONE) {
+		for (int i = 0; i < ps->o.blur_kernel_count; i++) {
+			free(ps->blur_kerns_cache[i]);
+		}
+		free(ps->blur_kerns_cache);
 	}
-	free(ps->blur_kerns_cache);
 }
 
 // vim: set ts=8 sw=8 noet :