bitbake: knotty: ignore interrupted system calls

With the improved exception handling added in an earlier commit bitbake
now stops when recieving a SIGWINCH. This happens frequently when
disconnecting and reconnecting tmux sessions and bitbake didn't survive.
Restore old behaviour of ignoring interrupted system calls but keep
proper exception handling for other errors.

(Bitbake rev: 418358a595c75f45b8d15160ec42bbe569562d91)

Signed-off-by: Dan McGregor <dan.mcgregor@usask.ca>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/ui/knotty.py

@@ -507,7 +507,7 @@ def main(server, eventHandler, params, tf = TerminalFilter):
             termfilter.clearFooter()
             # ignore interrupted io
             if ioerror.args[0] == 4:
-                pass
+                continue
             sys.stderr.write(str(ioerror))
             if not params.observe_only:
                 _, error = server.runCommand(["stateForceShutdown"])