code review 6700043: present: fix race condition

present: fix race condition
If one hits "Run" several times, then an old process removes the current process from c.proc.
As a result the new process can't be killed, and we end up with 2 processes running at the same time.

[dvyukov, 2012-10-15 16:07:18]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://dvyukov%40google.com@code.google.com/p/go.talks/

[adg, 2012-10-16 05:01:37]

LGTM

Thanks!

[adg, 2012-10-16 05:57:07]

Please hg sync and hg upload.

[dvyukov, 2012-10-16 06:35:45]

*** Submitted as
http://code.google.com/p/go/source/detail?r=a36292b60407&repo=talks ***

present: fix race condition
If one hits "Run" several times, then an old process removes the current process
from c.proc.
As a result the new process can't be killed, and we end up with 2 processes
running at the same time.

R=golang-dev, adg
CC=golang-dev
http://codereview.appspot.com/6700043