bump remote api to 1.12 & add --force-rm to build

This adds a `--force-rm` flag to docker build which makes the Docker
daemon clean up all containers, even when the build has failed.

This new flag requires that we bump the remote API, so we also bump the
remote API version.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)

docs/sources/reference/commandline/cli.md

@@ -192,6 +192,7 @@ To kill the container, use `docker kill`.
 
     Build a new container image from the source code at PATH
 
+      --force-rm=false     Always remove intermediate containers, even after unsuccessful builds
       --no-cache=false     Do not use cache when building the image
       -q, --quiet=false    Suppress the verbose output generated by the containers
       --rm=true            Remove intermediate containers after a successful build