Shared folder inheritence doesn't overwrite multi-vm [GH-1935]

CHANGELOG.md

@@ -6,6 +6,8 @@ BUG FIXES:
   - Debian/Ubuntu change hostname works properly if eth0 is configured
     with hot-plugging. [GH-1929]
   - NFS exports with improper casing on Mac OS X work properly. [GH-1202]
+  - Shared folders overriding '/vagrant' in multi-VM environments no
+    longer all just use the last value. [GH-1935]
 
 ## 1.2.4 (July 16, 2013)
 

plugins/kernel_v2/config/vm.rb

@@ -91,7 +91,11 @@ module VagrantPlugins
 
           # Merge synced folders.
           other_folders = other.instance_variable_get(:@__synced_folders)
-          new_folders = @__synced_folders.dup
+          new_folders = {}
+          @__synced_folders.each do |key, value|
+            new_folders[key] = value.dup
+          end
+
           other_folders.each do |id, options|
             new_folders[id] ||= {}
             new_folders[id].merge!(options)