Destroy old rpc handle for clean reconnection

Destroy old rpc handle for clean reconnection

- Issue:
When the client is disconnected, sometimes, the rpc handle can be
expired.

- Solution:
When the client is disconnected, the client should try to reconnect.
However, sometimes, the client can try to reconnect with expired rpc
handle. In this case, the client library can not create new rpc handle,
because current logic only makes new rpc handle if the function returns
I/O error. To resolve this issue, this patch destroyes the old handle
if the client is disconnected. Through this change, the client will be
sure to reconnect with new rpc handle.

Change-Id: Ic801abf2f69a291ca6b5c8748a67f987be81aa93
Signed-off-by: Suyeon Hwang <stom.hwang@samsung.com>