Extract cache error messages

Author: svivian

qa-include/Q2A/Storage/MemcachedDriver.php

@@ -59,7 +59,7 @@ public function __construct($config)
 				$this->setMemcachedError();
 			}
 		} else {
-			$this->error = 'The Memcached PHP extension is not installed';
+			$this->error = qa_lang_html('admin/no_memcached');
 		}
 	}
 
@@ -215,6 +215,6 @@ public function getStats()
 	 */
 	private function setMemcachedError()
 	{
-		$this->error = 'Memcached error: ' . $this->memcached->getResultMessage();
+		$this->error = qa_lang_html_sub('admin/memcached_error', $this->memcached->getResultMessage());
 	}
 }

qa-include/lang/qa-lang-admin.php

@@ -144,6 +144,7 @@
 	'mailing_unsubscribe' => 'An unsubscribe link will be added at the bottom of every message.',
 	'maintenance_admin_only' => 'Your site is in ^1maintenance^2 and is currently inaccessible to regular users.',
 	'maximum_x' => ' (max ^)',
+	'memcached_error' => 'Memcached error: ^',
 	'moderate_title' => 'Moderate',
 	'module_x_database_init' => 'The ^1 ^2 module requires some ^3database initialization^4.',
 	'most_flagged_title' => 'Flagged content',
@@ -157,6 +158,7 @@
 	'no_hidden_found' => 'No hidden content found',
 	'no_image_gd' => 'The installed version of PHP was compiled without GD image support, so users cannot upload their avatars directly.',
 	'no_link' => 'No link',
+	'no_memcached' => 'The Memcached PHP extension is not installed.',
 	'no_multibyte' => 'The installed version of PHP was compiled without multibyte string support. Searching will be less effective for non-Roman characters.',
 	'no_privileges' => 'Only administrators may access this page.',
 	'no_unapproved_found' => 'No users waiting for approval',