qtip bugfix: failed to clean up qtip container

qtip bugfix: failed to clean up qtip container

An error has happened a few times when stopping a container.
See
https://build.opnfv.org/ci/view/qtip/job/qtip-fuel-zte-pod2-daily-master/34/console.
Don't find the cause of this error temporarily.
Use the command "docker rm -f" to remove qtip container by force.
It is a workaround to make sure qtip ci job not blocked by this error.

According to ci log, sometimes, qtip containers are deleted failed.
This change use the command "docker rm -f" to delete containers
by force.

Change-Id: I063be9615f1b87e616ff8c3a77a6684a68474e91
Signed-off-by: wu.zhihui <wu.zhihui1@zte.com.cn>