Refactor removing query by get param

See https://github.com/marienfressinaud/FreshRSS/issues/625

app/Controllers/configureController.php

@@ -59,15 +59,7 @@ class FreshRSS_configure_Controller extends Minz_ActionController {
 					$catDAO->deleteCategory($ids[$key]);
 
 					// Remove related queries.
-					$final_queries = array();
-					$id_cat_in_query = 'c_' . $ids[$key];
-					foreach ($this->view->conf->queries as $key => $query) {
-						if (empty($query['get']) ||
-								$query['get'] !== $id_cat_in_query) {
-							$final_queries[$key] = $query;
-						}
-					}
-					$this->view->conf->_queries($final_queries);
+					$this->view->conf->remove_query_by_get('c_' . $ids[$key]);
 					$this->view->conf->save();
 				}
 			}

app/Models/Configuration.php

@@ -124,6 +124,16 @@ class FreshRSS_Configuration {
 		return $this->available_languages;
 	}
 
+	public function remove_query_by_get($get) {
+		$final_queries = array();
+		foreach ($this->queries as $key => $query) {
+			if (empty($query['get']) || $query['get'] !== $get) {
+				$final_queries[$key] = $query;
+			}
+		}
+		$this->_queries($final_queries);
+	}
+
 	public function _language($value) {
 		if (!isset($this->available_languages[$value])) {
 			$value = 'en';