Allow auto correct conflict port forwarding

Author: wangkuiyi

Vagrantfile

@@ -7,9 +7,12 @@ Vagrant.configure("2") do |config|
 
   # Don't forward 22.  Even if we do so, the exposed port only binds
   # to 127.0.0.1, but not 0.0.0.0.  Other ports binds to all IPs.
-  config.vm.network "forwarded_port", guest: 3306, host: 3306
-  config.vm.network "forwarded_port", guest: 50051, host: 50051
-  config.vm.network "forwarded_port", guest: 8888, host: 8888
+  config.vm.network "forwarded_port", guest: 3306, host: 3306,
+                    auto_correct: true
+  config.vm.network "forwarded_port", guest: 50051, host: 50051,
+                    auto_correct: true
+  config.vm.network "forwarded_port", guest: 8888, host: 8888,
+                    auto_correct: true
 
   config.vm.provider "virtualbox" do |v|
     v.memory = 16384