Comment 2 for bug 1495276

StacktraceTop:
 __assert_fail_base (fmt=0x7fed6ded1028 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion@entry=0x7fed6e80d132 "*_head == _item", file=file@entry=0x7fed6e80d117 "entrygroup.c", line=line@entry=245, function=function@entry=0x7fed6e80d3b0 "avahi_entry_group_free") at assert.c:92
 __GI___assert_fail (assertion=0x7fed6e80d132 "*_head == _item", file=0x7fed6e80d117 "entrygroup.c", line=245, function=0x7fed6e80d3b0 "avahi_entry_group_free") at assert.c:101
 avahi_entry_group_free () from /tmp/apport_sandbox_ge9Ymp/usr/lib/x86_64-linux-gnu/libavahi-client.so.3
 dnssdDeregisterInstance (srv=0x5613a662d9d0, from_callback=<optimized out>) at dirsvc.c:684
 dnssdDeregisterPrinter (p=0x5613a662d230, clear_name=clear_name@entry=1, from_callback=from_callback@entry=1) at dirsvc.c:711