vm/gce: work around GCE console bug
vm/gce: work around GCE console bug

Sometimes connects to serial console spuriously fail with:
Permission denied (publickey)

google/syzkaller,xairy/syzkaller,dotweiba/syzkaller,dotweiba/syzkaller,zoulasc/syzkaller,dotweiba/syzkaller,xairy/syzkaller,dotweiba/syzkaller,xairy/syzkaller,xairy/syzkaller,zoulasc/syzkaller,xairy/syzkaller,google/syzkaller,zoulasc/syzkaller,google/syzkaller,zoulasc/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller