Connection creation time is not reset when the connection itself is reset

[renecannao]

All ProxySQL with version >= 1.4.0 are affected.

PoxySQL 1.4.0 introduced a background thread (HGCU_thread_run()) responsible for resetting connections instead of dropping them when MySQL_HostGroups_Manager::destroy_MyConn_from_pool() is called.
Because creation_time is not reset, if mysql-connection_max_age_ms is set the connection is continuously reset when this age is reached.