Fix the GUI disconnect from the server

Fix https://github.com/GNS3/gns3-gui/issues/2084

gns3server/handlers/api/controller/link_handler.py

@@ -178,7 +178,6 @@ class LinkHandler:
                 response.content_type = "application/vnd.tcpdump.pcap"
                 response.set_status(200)
                 response.enable_chunked_encoding()
-                # Very important: do not send a content length otherwise QT closes the connection (curl can consume the feed)
                 yield from response.prepare(request)
 
                 while True:

gns3server/handlers/api/controller/project_handler.py

@@ -210,7 +210,6 @@ class ProjectHandler:
         response.content_type = "application/json"
         response.set_status(200)
         response.enable_chunked_encoding()
-        # Very important: do not send a content length otherwise QT closes the connection (curl can consume the feed)
 
         yield from response.prepare(request)
         with controller.notification.queue(project) as queue:
@@ -292,7 +291,6 @@ class ProjectHandler:
                 response.content_type = 'application/gns3project'
                 response.headers['CONTENT-DISPOSITION'] = 'attachment; filename="{}.gns3project"'.format(project.name)
                 response.enable_chunked_encoding()
-                # Very important: do not send a content length otherwise QT closes the connection (curl can consume the feed)
                 yield from response.prepare(request)
 
                 for data in datas:
@@ -404,7 +402,6 @@ class ProjectHandler:
         response.content_type = "application/octet-stream"
         response.set_status(200)
         response.enable_chunked_encoding()
-        # Very important: do not send a content length otherwise QT closes the connection (curl can consume the feed)
 
         try:
             with open(path, "rb") as f: