PHPRedis 5 compat. fix in session handler

program/lib/Roundcube/cache/redis.php

@@ -246,11 +246,8 @@ class rcube_cache_redis extends rcube_cache
             return false;
         }
 
-        if (method_exists(self::$redis, 'del')) {
-            $result = self::$redis->del($key);
-        } else {
-            $result = self::$redis->delete($key);
-        }
+        $fname  = method_exists(self::$redis, 'del') ? 'del' : 'delete';
+        $result = self::$redis->$fname($key);
 
         if ($this->debug) {
             $this->debug('delete', $key, null, $result);

program/lib/Roundcube/session/redis.php

@@ -79,7 +79,8 @@ class rcube_session_redis extends rcube_session {
     public function destroy($key)
     {
         if ($key) {
-            $result = $this->redis->del($key);
+            $fname  = method_exists($this->redis, 'del') ? 'del' : 'delete';
+            $result = $this->redis->$fname($key);
 
             if ($this->debug) {
                 $this->debug('delete', $key, null, $result);