add helper methods for detecting a remote docker host via the `DOCKER…

…_HOST` env var

files/tools/vagrant/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.7.4/plugins/providers/docker/provider.rb

@@ -1,6 +1,7 @@
 require "digest/md5"
 require "fileutils"
 require "thread"
+require "uri"
 
 require "log4r"
 
@@ -136,6 +137,17 @@ def host_vm?
         end
       end
 
+      # This checks whether the host system is configured to talk to a remote
+      # docker host by inspecting the `DOCKER_HOST` env var.
+      def remote_docker_host?
+        !ENV['DOCKER_HOST'].to_s.strip.empty?
+      end
+
+      # Returns the host part from the `DOCKER_HOST` env var
+      def remote_docker_host
+        URI.parse(ENV['DOCKER_HOST']).host
+      end
+
       # Returns the forwarded SSH port on the host. If no port forwarding
       # for "ssh" is found we return nil
       def forwarded_ssh_host_port