Reset instead of discard all (#549)

* Use reset all instead of discard all

* Move 'X' handling to before admin handle

* fix tests

src/client.rs

@@ -821,6 +821,14 @@ where
                 message_result = read_message(&mut self.read) => message_result?
             };
 
+            if message[0] as char == 'X' {
+                debug!("Client disconnecting");
+
+                self.stats.disconnect();
+
+                return Ok(());
+            }
+
             // Handle admin database queries.
             if self.admin {
                 debug!("Handling admin command");
@@ -940,14 +948,6 @@ where
                     continue;
                 }
 
-                'X' => {
-                    debug!("Client disconnecting");
-
-                    self.stats.disconnect();
-
-                    return Ok(());
-                }
-
                 // Close (F)
                 'C' => {
                     if prepared_statements_enabled {