puppet: Use $postgres_version in postgres template.

This eliminates hardcoding of the postgres version from the Zulip
puppet configuration.

puppet/zulip/manifests/postgres_appdb_tuned.pp

@@ -9,7 +9,7 @@ class zulip::postgres_appdb_tuned {
     owner  => "postgres",
     group  => "postgres",
     mode   => 644,
-    source => "puppet:///modules/zulip/postgresql/postgresql.conf.template"
+    content => template("zulip/postgresql/postgresql.conf.template.erb"),
   }
 
   # We can't use the built-in $memorysize fact because it's a string with human-readable units

puppet/zulip/templates/postgresql/postgresql.conf.template.erb

@@ -38,15 +38,15 @@
 # The default values of these variables are driven from the -D command-line
 # option or PGDATA environment variable, represented here as ConfigDir.
 
-data_directory = '/var/lib/postgresql/9.3/main'		# use data in another directory
+data_directory = '/var/lib/postgresql/<%= scope["zulip::base::postgres_version"] %>/main'		# use data in another directory
 					# (change requires restart)
-hba_file = '/etc/postgresql/9.3/main/pg_hba.conf'	# host-based authentication file
+hba_file = '/etc/postgresql/<%= scope["zulip::base::postgres_version"] %>/main/pg_hba.conf'	# host-based authentication file
 					# (change requires restart)
-ident_file = '/etc/postgresql/9.3/main/pg_ident.conf'	# ident configuration file
+ident_file = '/etc/postgresql/<%= scope["zulip::base::postgres_version"] %>/main/pg_ident.conf'	# ident configuration file
 					# (change requires restart)
 
 # If external_pid_file is not explicitly set, no extra PID file is written.
-external_pid_file = '/var/run/postgresql/9.3-main.pid'		# write an extra PID file
+external_pid_file = '/var/run/postgresql/<%= scope["zulip::base::postgres_version"] %>-main.pid'		# write an extra PID file
 					# (change requires restart)