Description of problem:
CheckpointRollback call does not remove newly created connections and devices even with NM_CHECKPOINT_CREATE_FLAG_DELETE_NEW_CONNECTIONS | NM_CHECKPOINT_CREATE_FLAG_DISCONNECT_NEW_DEVICES flags.

Version-Release number of selected component (if applicable):
CentOS 7.3.1611
NetworkManager-1.4.0-20

How reproducible:
Always

Steps to Reproduce:
1. Create a bridge and attach NIC to it.
2. Create a checkpoint.
3. Create another bridge and reattach NIC to it.
4. Start rollback.

Actual results:
Although NIC was reconnected to the original bridge, new bridge and its connection are still there.

Expected results:
New connection and created device will be removed when CheckpointCreate is called with flags NM_CHECKPOINT_CREATE_FLAG_DELETE_NEW_CONNECTIONS | NM_CHECKPOINT_CREATE_FLAG_DISCONNECT_NEW_DEVICES.

Reproducer script:
import dbus
import subprocess
import time

bus = dbus.SystemBus()
proxy = bus.get_object('org.freedesktop.NetworkManager', '/org/freedesktop/NetworkManager')
manager = dbus.Interface(proxy, 'org.freedesktop.NetworkManager')

# create a bridge and attach NIC to it
subprocess.check_call(['/usr/bin/nmcli', 'con', 'add', 'type', 'bridge', 'ifname', 'br1', 'autoconnect', 'yes', '--', 'connection.autoconnect-slaves', '1'])
subprocess.check_call(['/usr/bin/nmcli', 'con', 'add', 'type', 'ethernet', 'ifname', 'eth0', 'autoconnect', 'yes', '--', 'connection.master', 'br1', 'connection.slave-type', 'bridge'])
subprocess.check_call(['/usr/bin/nmcli', 'con', 'up', 'bridge-br1'])

time.sleep(2)

# create checkpoint
ALL_DEVICES = dbus.Array([], signature=dbus.Signature('ao'))
FOREVER = 0
NM_CHECKPOINT_CREATE_FLAG_DESTROY_ALL = 0x01
NM_CHECKPOINT_CREATE_FLAG_DELETE_NEW_CONNECTIONS = 0x02
NM_CHECKPOINT_CREATE_FLAG_DISCONNECT_NEW_DEVICES = 0x04
checkpoint = manager.CheckpointCreate(
    ALL_DEVICES,
    FOREVER,
    NM_CHECKPOINT_CREATE_FLAG_DESTROY_ALL |
    NM_CHECKPOINT_CREATE_FLAG_DELETE_NEW_CONNECTIONS |
    NM_CHECKPOINT_CREATE_FLAG_DISCONNECT_NEW_DEVICES
)

time.sleep(2)

# create another bridge and reattach NIC to it
subprocess.check_call(['/usr/bin/nmcli', 'con', 'down', 'bridge-br1'])
subprocess.check_call(['/usr/bin/nmcli', 'con', 'add', 'type', 'bridge', 'ifname', 'br2', 'autoconnect', 'yes', '--', 'connection.autoconnect-slaves', '1'])
subprocess.check_call(['/usr/bin/nmcli', 'con', 'modify', 'bridge-slave-eth0', 'connection.master', 'br2', 'connection.slave-type', 'bridge'])
subprocess.check_call(['/usr/bin/nmcli', 'con', 'up', 'bridge-br2'])

time.sleep(2)

# rollback to the checkpoint
manager.CheckpointRollback(checkpoint)


nmcli con show output:
NAME               UUID                                  TYPE            DEVICE 
bridge-br1         955c27cf-6948-43aa-bb82-026b2e798e68  bridge          br1    
bridge-br2         be417a69-1a83-4f4f-8567-0f80e97a9857  bridge          br2    
bridge-slave-eth0  7403cede-e1cb-4138-88dc-dba4f2e6a4ff  802-3-ethernet  eth0   
System eth0        5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03  802-3-ethernet  --

ip link output:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master br1 state UP mode DEFAULT qlen 1000
    link/ether 52:54:00:55:e6:7c brd ff:ff:ff:ff:ff:ff
41: br2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT qlen 1000
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
42: br1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT qlen 1000
    link/ether 52:54:00:55:e6:7c brd ff:ff:ff:ff:ff:ff