Turn network, provider, and provisioner names into symbols if not

CHANGELOG.md

@@ -6,6 +6,8 @@ IMPROVEMENTS:
     are avoided. [GH-1418]
   - An error will be shown if you forward a port to the same host port
     multiple times.
+  - Automatically convert network, provider, and provisioner names to
+    symbols internally in case people define them as strings.
 
 BUG FIXES:
 

plugins/kernel_v2/config/vm.rb

@@ -138,19 +138,20 @@ module VagrantPlugins
         end
 
         # Merge in the latest settings and set the internal state
-        @__networks[id] = [type, options]
+        @__networks[id] = [type.to_sym, options]
       end
 
       # Configures a provider for this VM.
       #
       # @param [Symbol] name The name of the provider.
       def provider(name, &block)
+        name = name.to_sym
         @__providers[name] ||= []
         @__providers[name] << block if block_given?
       end
 
       def provision(name, options=nil, &block)
-        @provisioners << VagrantConfigProvisioner.new(name, options, &block)
+        @provisioners << VagrantConfigProvisioner.new(name.to_sym, options, &block)
       end
 
       def defined_vms