Fix creating asyncio task in Python 3.6

gns3server/utils/asyncio/pool.py

@@ -15,6 +15,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import sys
 import asyncio
 
 
@@ -39,7 +40,11 @@ class Pool():
         while len(self._tasks) > 0 or len(pending) > 0:
             while len(self._tasks) > 0 and len(pending) < self._concurrency:
                 task, args, kwargs = self._tasks.pop(0)
-                pending.add(asyncio.create_task(task(*args, **kwargs)))
+                if sys.version_info >= (3, 7):
+                    t = asyncio.create_task(task(*args, **kwargs))
+                else:
+                    t = asyncio.get_event_loop().create_task(task(*args, **kwargs))
+                pending.add(t)
             (done, pending) = await asyncio.wait(pending, return_when=asyncio.FIRST_COMPLETED)
             for task in done:
                 if task.exception():