Add binary_url attribute back

This attribute allows users to override the complete binary URL in case
they want to download it from a source other than hashicorp's
release page.

Author: trotttrotttrott

attributes/default.rb

@@ -10,10 +10,12 @@
 
 default["serf"]["event_handlers"] = []
 
-default["serf"]["base_binary_url"] = "https://releases.hashicorp.com/serf/"
 default["serf"]["version"] = "0.7.0"
 default['serf']['arch'] = kernel['machine'] =~ /x86_64/ ? "amd64" : "386"
 
+default["serf"]["base_binary_url"] = "https://releases.hashicorp.com/serf/"
+default["serf"]["binary_url"] = nil
+
 default["serf"]["base_directory"] = "/opt/serf"
 default["serf"]["log_directory"] = "/var/log/serf"
 default["serf"]["conf_directory"] = "/etc/serf"

libraries/serf_helper.rb

@@ -49,7 +49,8 @@ def get_zip_file_path
   end
 
   def get_binary_url
-    File.join node["serf"]["base_binary_url"], node["serf"]["version"], get_binary_filename
+    node["serf"]["binary_url"] ||
+    File.join(node["serf"]["base_binary_url"], node["serf"]["version"], get_binary_filename)
   end
 
   def get_serf_installed_version