Fix warnings in tests

tests/controller/gns3vm/test_remote_gns3_vm.py

@@ -55,7 +55,7 @@ async def test_start(gns3vm, controller):
     assert gns3vm.password == "world"
 
 
-async def test_start_invalid_vm(loop, gns3vm, controller):
+async def test_start_invalid_vm(event_loop, gns3vm, controller):
 
     await controller.add_compute("r1",
                                  name="R1",

tests/controller/gns3vm/test_virtualbox_gns3_vm.py

@@ -25,7 +25,7 @@ from gns3server.controller.gns3vm.virtualbox_gns3_vm import VirtualBoxGNS3VM
 
 
 @pytest.fixture
-async def gns3vm(loop, controller):
+async def gns3vm(event_loop, controller):
 
     vm = VirtualBoxGNS3VM(controller)
     vm.vmname = "GNS3 VM"

tests/controller/gns3vm/test_vmware_gns3_vm.py

@@ -21,7 +21,7 @@ from gns3server.controller.gns3vm.vmware_gns3_vm import VMwareGNS3VM
 
 
 @pytest.fixture
-async def gns3vm(loop, controller):
+async def gns3vm(event_loop, controller):
 
     vm = VMwareGNS3VM(controller)
     vm.vmname = "GNS3 VM"