runsc: Fix "exec" command when called without --pid-file.

When "exec" command is called without the "--detach" flag, we spawn a second
"exec" command and wait for that one to start. We use the pid file passed in
--pid-file to detect when this second command has started running.

However if "exec" is called with no --pid-file flag, this system breaks down,
as we don't have a pid file to wait for.

This CL ensures that the second instance of the "exec" command always writes a
pid-file, so the wait is successful.

PiperOrigin-RevId: 206002403
Change-Id: If9f2be31eb6e831734b1b833f25054ec71ab94a6

0 files changed, 0 insertions, 0 deletions