metrics: Remove sleep while shutting down multiple containers

[GabyCT]

Now that this issue has been solved kata-containers/agent#263,
it is necessary to remove the workaround of sleeping while shutting down containers.

Fixes #635

Signed-off-by: Gabriela Cervantes [email protected]

[devimc]

lgtm

[grahamwhaley]

l g t m - and, whilst you are there, there is another instance over at https://github.com/kata-containers/tests/blob/master/metrics/density/footprint_data.sh#L160
Can you add that to this PR as well pls? :-)

I believe the use of rm -f is fine/correct - it will have the same effect. Just wanted to check we were not going to end up issuing a 'STOP' to the container, as that then introduces a 10s extra delay (whilst the STOP is ignored by most of the containers).

[grahamwhaley]

Re-kicking 16.04 CI. afaict, it failed the log parser:

ERROR: kata-log-parser: failed to parse agent log entry {Count:0 TimeDelta:0 Filename:/tmp/jenkins/workspace/kata-containers-tests-ubuntu-16-04-PR/go/src/github.com/kata-containers/tests/kata-proxy.log Line:45878 Time:2018-08-22 20:48:42.641204298 +0000 UTC Pid:3089 Level:info Msg:time="2018-08-22T20:48:42.58584803Z" level=debug msg="new request" name=kata-agent pid=96 

[grahamwhaley]

oh, I guess I should have marked that as 'request changes then' - as noted, there is another ocurrence of this that could have been fixed at the same time. @GabyCT - guess that will have to go on a new PR now.
I'll be a bit firmer with the github flow in future then...