group_ctx->name is only used in this one function, and for now it

corresponds directly to the static list of group names. Just use the
static list and stop strdup()ing a new version for the context struct.
Since that never got freed this also fixes a small memleak.

Kill some unused variables while i'm here.

ok okan@

calmwm.h

@@ -171,7 +171,6 @@ static char *shortcut_to_name[] = {
 struct group_ctx {
 	TAILQ_ENTRY(group_ctx)	 entry;
 	struct client_ctx_q	 clients;
-	char			*name;
 	int			 shortcut;
 	int			 hidden;
 	int			 nhidden;