Avoid division by zero issues in the automatically triggered AOF rewrite feature.

src/redis.c

@@ -695,8 +695,9 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
          if (server.auto_aofrewrite_perc &&
              server.appendonly_current_size > server.auto_aofrewrite_min_size)
          {
-            int growth = (server.appendonly_current_size*100/
-                          server.auto_aofrewrite_base_size);
+            int base = server.auto_aofrewrite_base_size ?
+                            server.auto_aofrewrite_base_size : 1;
+            int growth = (server.appendonly_current_size*100/base);
             if (growth >= server.auto_aofrewrite_perc) {
                 redisLog(REDIS_NOTICE,"Starting automatic rewriting of AOF on %d growth",growth);
                 rewriteAppendOnlyFileBackground();