Auto rewrite integer overflow fixed. Thanks to Gaurav for finding it (see...

Auto rewrite integer overflow fixed. Thanks to Gaurav for finding it (see issue 602 on google code), and Pieter Noordhuis for tracing it.

src/redis.c

@@ -685,7 +685,7 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
              server.auto_aofrewrite_perc &&
              server.appendonly_current_size > server.auto_aofrewrite_min_size)
          {
-            int base = server.auto_aofrewrite_base_size ?
+            long long base = server.auto_aofrewrite_base_size ?
                             server.auto_aofrewrite_base_size : 1;
             long long growth = (server.appendonly_current_size*100/base) - 100;
             if (growth >= server.auto_aofrewrite_perc) {