Don't make the user get a container alreayd exists error

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Merge pull request #6865 from SvenDowideit/remove-the-named-container-before-creating-a-new-one

Don't make the user get a container already exists error