Stop writes on MISCONF only if instance is a master.

From the point of view of the slave not accepting writes from the master
can only create a bigger consistency issue.

src/redis.c

@@ -1918,10 +1918,12 @@ int processCommand(redisClient *c) {
         }
     }
 
-    /* Don't accept write commands if there are problems persisting on disk. */
+    /* Don't accept write commands if there are problems persisting on disk
+     * and if this is a master instance. */
     if (server.stop_writes_on_bgsave_err &&
         server.saveparamslen > 0
         && server.lastbgsave_status == REDIS_ERR &&
+        server.masterhost != NULL &&
         (c->cmd->flags & REDIS_CMD_WRITE ||
          c->cmd->proc == pingCommand))
     {
@@ -1931,7 +1933,7 @@ int processCommand(redisClient *c) {
     }
 
     /* Don't accept write commands if there are not enough good slaves and
-     * used configured the min-slaves-to-write option. */
+     * user configured the min-slaves-to-write option. */
     if (server.repl_min_slaves_to_write &&
         server.repl_min_slaves_max_lag &&
         c->cmd->flags & REDIS_CMD_WRITE &&