Fixing hang when closing connection without any channel.
Fixing hang when closing connection without any channel.

pika/pika,zixiliuyue/pika,reddec/pika,fkarb/pika-python3,jstnlef/pika,benjamin9999/pika,renshawbay/pika-python3,vitaly-krugl/pika,vrtsystems/pika,Tarsbot/pika,Zephor5/pika,skftn/pika,shinji-s/pika,hugoxia/pika,knowsis/pika