synced_folders/rsync: run hostpath through fs_real_path

This fixes issues with drive letter casing on Windows

lib/vagrant/util/platform.rb

@@ -60,7 +60,18 @@ module Vagrant
         # of the path.
         def fs_real_path(path)
           path = Pathname.new(File.expand_path(path))
-          raise "Path must exist for path expansion" if !path.exist?
+
+          if windows?
+            # Fix the drive letter to be uppercase.
+            path = path.to_s
+            if path[1] == ":"
+              path[0] = path[0].upcase
+            end
+
+            path = Pathname.new(path)
+          end
+
+          return path if !path.exist?
           return path if fs_case_sensitive?
 
           # Build up all the parts of the path

plugins/synced_folders/rsync/helper.rb

@@ -1,3 +1,4 @@
+require "vagrant/util/platform"
 require "vagrant/util/subprocess"
 
 module VagrantPlugins
@@ -10,6 +11,7 @@ module VagrantPlugins
         guestpath = opts[:guestpath]
         hostpath  = opts[:hostpath]
         hostpath  = File.expand_path(hostpath, machine.env.root_path)
+        hostpath  = Vagrant::Util::Platform.fs_real_path(hostpath).to_s
 
         # Connection information
         username = ssh_info[:username]

test/unit/plugins/synced_folders/rsync/helper_test.rb

@@ -1,5 +1,7 @@
 require_relative "../../../base"
 
+require "vagrant/util/platform"
+
 require Vagrant.source_root.join("plugins/synced_folders/rsync/helper")
 
 describe VagrantPlugins::SyncedFolderRSync::RsyncHelper do
@@ -56,7 +58,7 @@ describe VagrantPlugins::SyncedFolderRSync::RsyncHelper do
         opts[:guestpath] = "/bar"
 
         Vagrant::Util::Subprocess.should_receive(:execute).with do |*args|
-          expect(args[args.length - 3]).to eql("/foo")
+          expect(args[args.length - 3]).to eql(Vagrant::Util::Platform.fs_real_path("/foo").to_s)
           expect(args[args.length - 2]).to include("/bar")
         end