core: dup option hashes everywhere

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 BUG FIXES:
 
+  - core: Fix various issues where using the same options hash in a
+    Vagrantfile can cause errors.
   - provisioners/puppet: No more "shared folders cannot be found" error.
     [GH-2134]
 

plugins/kernel_v2/config/vm.rb

@@ -163,6 +163,7 @@ module VagrantPlugins
       # @param [Hash] options Options for the network.
       def network(type, options=nil)
         options ||= {}
+        options = options.dup
         options[:protocol] ||= "tcp"
 
         if !options[:id]
@@ -226,6 +227,7 @@ module VagrantPlugins
       def define(name, options=nil, &block)
         name = name.to_sym
         options ||= {}
+        options = options.dup
         options[:config_version] ||= "2"
 
         # Add the name to the array of VM keys. This array is used to