don't track context manager status for BackgroundHTTPServer

There is actually no possible case where __exit__ would be called
without __enter__, even if the server is used in an existing
context manager block.

The only case to ever legitimately call __exit__ is if the instance
was created by a context manager in the first place, and __enter__
was called.

Signed-off-by: Jiri Jaburek <comps@nomail.dom>

lib/util/httpsrv.py

@@ -89,7 +89,6 @@ def log_message(self, form, *args):
 class BackgroundHTTPServer:
     def __init__(self, host, port):
         self.server = None
-        self.created_by_context = False
         self.file_mapping = {}
         self.dir_mapping = {}
         self.requested_address = (host, port)
@@ -192,9 +191,7 @@ def stop(self):
                 stdout=subprocess.DEVNULL, check=True)
 
     def __enter__(self):
-        self.created_by_context = True
         return self
 
     def __exit__(self, exc_type, exc_value, traceback):
-        if self.created_by_context:
-            self.stop()
+        self.stop()