coccinelle: automatically rewrite memset() to zero() or memzero() where we can

We are pretty good at this already, hence only a single case is actually
found by this.

coccinelle/memzero.cocci

@@ -0,0 +1,30 @@
+@@
+expression s;
+@@
+- memset(&s, 0, sizeof(s))
++ zero(s)
+@@
+expression s;
+@@
+- memset(s, 0, sizeof(*s))
++ zero(*s)
+@@
+expression s;
+@@
+- bzero(&s, sizeof(s))
++ zero(s)
+@@
+expression s;
+@@
+- bzero(s, sizeof(*s))
++ zero(*s)
+@@
+expression a, b;
+@@
+- memset(a, 0, b)
++ memzero(a, b)
+@@
+expression a, b;
+@@
+- bzero(a, b)
++ memzero(a, b)

src/journal/journald-server.c

@@ -133,7 +133,7 @@ static int determine_path_usage(Server *s, const char *path, uint64_t *ret_used,
 }
 
 static void cache_space_invalidate(JournalStorageSpace *space) {
-        memset(space, 0, sizeof(*space));
+        zero(*space);
 }
 
 static int cache_space_refresh(Server *s, JournalStorage *storage) {