cooker: gracefully shutdown parsers

CookerParser.shutdown code doesn't do all required work to shutdown parser processes. As a result bitbake hangs if interrupted during parsing. Putting None into the parser_quit queue should fix this issue as it makes parsers to quit main loop.

---
 bitbake/lib/bb/cooker.py | 1 +
 1 file changed, 1 insertion(+)

index af3d77b..43e9f18 100644
@@ -2058,6 +2058,7 @@ class CookerParser(object):
             self.feeder_quit.put(None)
             for process in self.processes:
                 self.jobs.put(None)
+                self.parser_quit.put(None)
         else:
             self.feeder_quit.put('cancel')
 

2.1.4