Do not wait auto start to finish in order to complete project opening

Fix https://github.com/GNS3/gns3-gui/issues/2074

gns3server/controller/project.py

@@ -675,7 +675,10 @@ class Project:
         self._loading = False
         # Should we start the nodes when project is open
         if self._auto_start:
-            yield from self.start_all()
+            # Start all in the background without waiting for completion
+            # we ignore errors because we want to let the user open
+            # their project and fix it
+            asyncio.async(self.start_all())
 
     @asyncio.coroutine
     def wait_loaded(self):

tests/utils.py

@@ -18,6 +18,7 @@
 import io
 import asyncio
 import unittest.mock
+import collections.abc
 
 
 class _asyncio_patch:
@@ -69,6 +70,7 @@ class AsyncioMagicMock(unittest.mock.MagicMock):
     """
     Magic mock returning coroutine
     """
+    __class__ = collections.abc.Awaitable
 
     def __init__(self, return_value=None, return_values=None, **kwargs):
         """