PXC-594 PXC-608: Assertion `sender->count_last_applied' failed in gcs_group_handle_join_msg(gcs_group_t*, const gcs_recv_msg_t*)

[sysprg]

This patch fixes two bugs:

PART I, PXC-594:

Assertion `sender->count_last_applied' failed in the gcs_group_handle_join_msg() function.

This error stems from the fact that we have added a direct transition from JOINED to DONOR state bypassing SYNCED state, but does not take into account that in this case the count_last_applied flag is lost. It is necessary to change it in such a direct transition.

PART II, PXC-608:

Assertion `node->desync_count > 0' failed in the the gcs_node_update_status() function.

This error occurs because although disconnection node from the cluster involves stop of replication, closing of all client connections and consequently the cancellation of all transactions (which are tied to client connections), but the desynchronization counter associated with the current node, as well as the last state of the node, which is stored in the prim_state field of the gcs_group_t structure, are not cleared even after disconnecting the node from the cluster.

Related PXC patch is located here: https://github.com/percona/percona-xtradb-cluster/pull/360