Do not copy symlinks to VM for integration tests

This change updates the rsync command for the Vagrantfile to not copy
symlinks to the underlying VM. This is due to the fact that `dep` does
not prune symlinks, and a broken symlink that is included by a vendored
dependency breaks the default `rsync` command. See
golang/dep#1625 for more context.

Vagrantfile

@@ -25,7 +25,12 @@ Vagrant.configure('2') do |config|
 
   agent_dir = '/home/vagrant/go/src/github.com/cloudfoundry/bosh-agent'
 
-  config.vm.synced_folder '.', agent_dir, type: "rsync"
+  # We need to override the rsync args to exlucde "--copy-links".
+  # This is due to the fact that `dep` does not prune symlinks from the vendor directory.
+  # A vendored dependency has a broken symlink for test, which breaks `rsync`.
+  # See https://github.com/golang/dep/issues/1625 for more context
+  config.vm.synced_folder '.', agent_dir, type: "rsync",
+    rsync__args: ["--verbose", "--archive", "--delete", "-z"]
 
 #  config.vm.synced_folder Dir.pwd, '/vagrant', disabled: true
   config.vm.provision :shell, inline: "mkdir -p /vagrant && chmod 777 /vagrant"