[nrf fromtree] Bluetooth: Mesh: remove device key candidate

Commit removes device key candidate if provisionee failed
during device key refresh procedure or mesh reset has been
called in between. Otherwise, device key candidate gets
stuck in the internal trusted storage of crypto library.

Signed-off-by: Aleksandr Khromykh <aleksandr.khromykh@nordicsemi.no>
(cherry picked from commit bf22fa6)
Signed-off-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>

Author: alxelax

subsys/bluetooth/mesh/main.c

@@ -237,6 +237,8 @@ void bt_mesh_dev_key_cand_remove(void)
 	}
 
 	LOG_DBG("");
+	bt_mesh_key_destroy(&bt_mesh.dev_key_cand);
+	memset(&bt_mesh.dev_key_cand, 0, sizeof(struct bt_mesh_key));
 
 	if (IS_ENABLED(CONFIG_BT_SETTINGS)) {
 		bt_mesh_net_dev_key_cand_store();
@@ -398,6 +400,10 @@ void bt_mesh_reset(void)
 	bt_mesh_key_destroy(&bt_mesh.dev_key);
 	memset(&bt_mesh.dev_key, 0, sizeof(bt_mesh.dev_key));
 
+	if (IS_ENABLED(CONFIG_BT_MESH_RPR_SRV)) {
+		bt_mesh_dev_key_cand_remove();
+	}
+
 	bt_mesh_beacon_disable();
 
 	bt_mesh_comp_unprovision();