Execution time limit doesn't work as expected

[dtuantran]

competitions-v1-compute-worker/worker.py

Line 502 in 3d2ff02

'--stop-timeout={}'.format(execution_time_limit),

The way we implement execution_time_limit in docker command doesn't work as we expected. This option doesn't stop the container after this limit time.
Here is Docker documentation : https://docs.docker.com/engine/reference/commandline/run/#stop-timeout

"The --stop-timeout flag sets the number of seconds to wait for the container to stop after sending the pre-defined (see --stop-signal) system call signal. If the container does not exit after the timeout elapses, it's forcibly killed with a SIGKILL signal.

If you set --stop-timeout to -1, no timeout is applied, and the daemon waits indefinitely for the container to exit.

The Daemon determines the default, and is 10 seconds for Linux containers, and 30 seconds for Windows containers."