Merge pull request #3783 from YungSang/topic

kernel/v2: set disabled to false whenever synced folder override

plugins/kernel_v2/config/vm.rb

@@ -186,6 +186,7 @@ module VagrantPlugins
         options ||= {}
         options[:guestpath] = guestpath.to_s.gsub(/\/$/, '')
         options[:hostpath]  = hostpath
+        options[:disabled]  = options[:disabled] || false
         options = (@__synced_folders[options[:guestpath]] || {}).
           merge(options.dup)
 

test/unit/plugins/kernel_v2/config/vm_test.rb

@@ -418,7 +418,7 @@ describe VagrantPlugins::Kernel_V2::VMConfig do
       sf = subject.synced_folders
       expect(sf.length).to eq(1)
       expect(sf).to have_key("/vagrant")
-      expect(sf["/vagrant"][:disabled]).to be_true
+      expect(sf["/vagrant"][:disabled]).to be_false
       expect(sf["/vagrant"][:foo]).to eq(:bar)
     end
   end