remove bundled pureftpd_merge() function

The pureftpd_merge() function included in this module is a copy of the
stdlib merge() function from commit id
f496005bf3db8a5202bf9c16daf9a524b178c67a.  This version of merge()
includes a critical bug fix that was commit after the stdlib 4.1.0
release.  Now that stdlib 4.2.0 has been released (finally!) with the
needed fix, bundling a version of the merge() function in this module is
no longer necessary.

Author: Joshua Hoblitt

.fixtures.yml

@@ -2,6 +2,6 @@ fixtures:
   repositories:
     "stdlib":
       repo: "git://github.com/puppetlabs/puppetlabs-stdlib.git"
-      ref: "4.0.0"
+      ref: "4.2.0"
   symlinks:
     "pureftpd": "#{source_dir}"

Modulefile

@@ -7,4 +7,4 @@ project_page 'https://github.com/jhoblitt/puppet-pureftpd'
 source 'https://github.com/jhoblitt/puppet-pureftpd.git'
 summary 'Manages the pure-ftpd package with comprehensive configuration support'
 description 'Manages the pure-ftpd package with comprehensive configuration support'
-dependency 'puppetlabs/stdlib', '>= 4.0.0'
+dependency 'puppetlabs/stdlib', '>= 4.2.0'

lib/puppet/parser/functions/pureftpd_merge.rb

@@ -62,7 +62,7 @@
     $enable_ldap = { ldapconfigfile => $pureftpd::params::ldap_conf_path }
 
     # instantiate a pureftpd::config::ldap that will notify the service class
-    $safe_config_ldap = pureftpd_merge($config_ldap,
+    $safe_config_ldap = merge($config_ldap,
       { notify => Class[ 'pureftpd::service' ] }
     )
     create_resources( 'class',
@@ -80,7 +80,7 @@
     $enable_mysql = { mysqlconfigfile => $pureftpd::params::mysql_conf_path }
 
     # instantiate a pureftpd::config::mysql that will notify the service class
-    $safe_config_mysql = pureftpd_merge($config_mysql,
+    $safe_config_mysql = merge($config_mysql,
       { notify => Class[ 'pureftpd::service' ] }
     )
     create_resources( 'class',
@@ -98,7 +98,7 @@
     $enable_pgsql = { pgsqlconfigfile => $pureftpd::params::pgsql_conf_path }
 
     # instantiate a pureftpd::config::mysql will notify the service class
-    $safe_config_pgsql = pureftpd_merge($config_pgsql,
+    $safe_config_pgsql = merge($config_pgsql,
       { notify => Class[ 'pureftpd::service' ] }
     )
     create_resources( 'class',
@@ -112,7 +112,7 @@
     Class[ 'pureftpd::config::pgsql' ]
   }
 
-  $safe_config = pureftpd_merge(
+  $safe_config = merge(
     $config,
     { notify => Class[ 'pureftpd::service' ] },
     $enable_ldap,