find: insert -a in before open parens as well

This fixes expressions like -type f '(' -name foo -o -name bar ')'.

find.c

@@ -802,7 +802,8 @@ parse(int argc, char **argv)
 		} else if ((op = find_op(*arg))) { /* token is an operator */
 			if (lasttype == LPAR && op->type == RPAR)
 				eprintf("empty parens\n");
-			if ((lasttype == PRIM || lasttype == RPAR) && op->type == NOT) { /* need another implicit -a */
+			if ((lasttype == PRIM || lasttype == RPAR) &&
+			    (op->type == NOT || op->type == LPAR)) { /* need another implicit -a */
 				*tok++ = and;
 				ntok++;
 			}