i18n: en-GB revert

https://github.com/FreshRSS/FreshRSS/commit/af166f6c5344d727744e08d22f605cc57ec618f8#commitcomment-11229341

app/i18n/en/install.php

@@ -3,7 +3,7 @@
 return array(
 	'action' => array(
 		'finish' => 'Complete installation',
-		'fix_errors_before' => 'Please fix errors before before skipping to the next step.',
+		'fix_errors_before' => 'Please fix errors before skipping to the next step.',
 		'next_step' => 'Go to the next step',
 	),
 	'auth' => array(
@@ -91,7 +91,7 @@ return array(
 	'congratulations' => 'Congratulations!',
 	'default_user' => 'Username of the default user <small>(maximum 16 alphanumeric characters)</small>',
 	'delete_articles_after' => 'Remove articles after',
-	'fix_errors_before' => 'Please fix errors before before skipping to the next step.',
+	'fix_errors_before' => 'Please fix errors before skipping to the next step.',
 	'javascript_is_better' => 'FreshRSS is more pleasant with JavaScript enabled',
 	'language' => array(
 		'_' => 'Language',