config_version: Show the compiling master's name

Prior to this, the config_version script just showed the commit ID of
the version of code being compiled. This commit includes the compiling
Puppet master's hostname and environment name in the config_version.
This is very useful for debugging when a Puppet master is failing and
you have multiple masters behind a load balancer.

The output of config_version now looks like this:

pupmaster01-production-ac9785273a10

1 files changed, 11 insertions, 3 deletions

diff --git a/scripts/code_manager_config_version.rb b/scripts/code_manager_config_version.rb
index 2c9cb62..1ef62af 100755
--- a/scripts/code_manager_config_version.rb
+++ b/scripts/code_manager_config_version.rb
@@ -1,10 +1,18 @@
-#!/usr/bin/env ruby
+#!/opt/puppetlabs/puppet/bin/ruby
 require 'json'
+require 'socket'
 
 environmentpath = ARGV[0]
 environment     = ARGV[1]
 
+# Get the hostname of the Puppet master compiling the catalog.
+compiling_master = Socket.gethostname
+
+# Get the path to the Code Manager deployment info file.
 r10k_deploy_file_path = File.join(environmentpath, environment, '.r10k-deploy.json')
 
-#output the sha1 from the control-repo
-puts JSON.parse(File.read(r10k_deploy_file_path))['signature']
+# Get the first 12 characters of the commit ID out of the deployment file.
+commit_id = JSON.parse(File.read(r10k_deploy_file_path))['signature'][0...11]
+
+# Show the compiling master, environment name, and commit ID.
+puts "#{compiling_master}-#{environment}-#{commit_id}"