Merge branch '2.2' into 3.0

# Conflicts:
#	gns3server/compute/builtin/nodes/cloud.py
#	gns3server/compute/vmware/vmware_vm.py
#	gns3server/controller/link.py
#	gns3server/controller/snapshot.py
#	gns3server/handlers/api/compute/dynamips_vm_handler.py
#	gns3server/handlers/api/compute/iou_handler.py
#	gns3server/handlers/api/compute/qemu_handler.py
#	gns3server/handlers/api/controller/link_handler.py
#	gns3server/schemas/link.py
#	gns3server/utils/path.py
#	gns3server/version.py
#	requirements.txt

gns3server/compute/builtin/nodes/cloud.py

@@ -430,6 +430,7 @@ class Cloud(BaseNode):
             await self._add_ubridge_connection(nio, port_number)
             self._nios[port_number] = nio
         except (NodeError, UbridgeError) as e:
+            log.error('Cannot add NIO on cloud "{name}": {error}'.format(name=self._name, error=e))
             await self._stop_ubridge()
             self.status = "stopped"
             self._nios[port_number] = nio