client: Avoid memory leak in fio_client_handle_iolog()

client:  Avoid memory leak in fio_client_handle_iolog()

The actual code was returning in different places without freeing some pointers in some cases.

We have two places where memory was allocated :
 - pdu = convert_iolog
 - log_pathname = malloc ()

This patch creates a label to manage the return code while checking if
those two pointers needs to be freed.

Signed-off-by: Erwan Velu <erwan@redhat.com>