puppet: Allow passing an alternate config path to zulip-puppet-apply.

When temporary configuration changes are desired, this lets one set up
an alternate `zulip.conf` to apply while leaving the true one in place.

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

@@ -2,7 +2,8 @@ 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=$?.success?
+    zulip_conf_path = lookupvar('zulip_conf_path')
+    output = `/usr/bin/crudini --get #{zulip_conf_path} #{joined} 2>&1`; result=$?.success?
     if result
       output.strip()
     else

scripts/zulip-puppet-apply

@@ -14,10 +14,13 @@ BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 parser = argparse.ArgumentParser(description="Run puppet")
 parser.add_argument('--force', '-f', action="store_true",
                     help="Do not prompt with proposed changes")
+parser.add_argument('--config', action="store",
+                    default="/etc/zulip/zulip.conf",
+                    help="Alternate zulip.conf path")
 args, extra_args = parser.parse_known_args()
 
 config = configparser.RawConfigParser()
-config.read("/etc/zulip/zulip.conf")
+config.read(args.config)
 
 distro_info = parse_os_release()
 puppet_config = """
@@ -35,6 +38,7 @@ puppet_cmd += extra_args
 
 # Set the scripts path to be a factor so it can be used by puppet code
 puppet_env = os.environ.copy()
+puppet_env["FACTER_zulip_conf_path"] = args.config
 puppet_env["FACTER_zulip_scripts_path"] = scripts_path
 
 # This is to suppress puppet warnings with ruby 2.7.