puppet: add zulipconf function for reading settings from zulip.conf.

This makes it convenient for us to have optional user-defined settings
in the main Zulip puppet configuration.

puppet/zulip/lib/puppet/parser/functions/zulipconf.rb

@@ -0,0 +1,12 @@
+module Puppet::Parser::Functions
+  newfunction(:zulipconf, :type => :rvalue) do |args|
+    default = args.pop
+    joined = args.join(" ")
+    output = `/usr/bin/crudini --get /etc/zulip/zulip.conf #{joined} 2>&1`; result=$?.success?
+    if result
+      output
+    else
+      default
+    end
+  end
+end

scripts/lib/install

@@ -19,7 +19,7 @@ VIRTUALENV_NEEDED="${VIRTUALENV_NEEDED:-yes}"
 
 apt-get update
 apt-get -y dist-upgrade $APT_OPTIONS
-apt-get install -y puppet git python python-six $ADDITIONAL_PACKAGES
+apt-get install -y puppet git python python-six crudini $ADDITIONAL_PACKAGES
 
 # Create and activate a virtualenv
 if [ "$VIRTUALENV_NEEDED" = "yes" ]; then