if catch 409 error code when delete a unempty caontainer, will clean up the container and try delete it again
resolve 409
Merge branch '0.4.1.0' of https://github.com/xiaoerlyl/cosbench into 0.4.1.0
optional configuration for generating histogram
Merge pull request #230 from xiaoerlyl/0.4.1.0

resolve issue #48