Merge branch '2.1' into 2.2

# Conflicts:
#	gns3server/compute/docker/docker_vm.py
#	gns3server/controller/compute.py
#	gns3server/controller/gns3vm/__init__.py
#	gns3server/controller/link.py
#	gns3server/controller/project.py
#	gns3server/handlers/api/controller/project_handler.py
#	gns3server/handlers/api/controller/server_handler.py
#	gns3server/utils/asyncio/__init__.py
#	gns3server/utils/asyncio/telnet_server.py
#	gns3server/version.py
#	gns3server/web/web_server.py
#	tests/compute/qemu/test_qemu_vm.py

gns3server/controller/snapshot.py

@@ -101,7 +101,7 @@ class Snapshot:
             with tempfile.TemporaryDirectory() as tmpdir:
                 zipstream = yield from export_project(self._project, tmpdir, keep_compute_id=True, allow_all_nodes=True)
                 yield from wait_run_in_executor(self._create_snapshot_file, zipstream)
-        except OSError as e:
+        except (ValueError, OSError, RuntimeError) as e:
             raise aiohttp.web.HTTPConflict(text="Could not create snapshot file '{}': {}".format(self.path, e))
 
     @asyncio.coroutine