Fixing error connecting to a remote daemon over ssh

[jjbustamante]

Summary

This PR just fixes an error connecting with a remote daemon over ssh, the only thing I did was to remove a trailing slash in at this line added by this PR

Before

I managed to reproduce the error

> DOCKER_HOST=ssh://[email protected] /Users/jbustamante/go/src/github.com/buildpacks/pack/out/pack build -p ruby-bundler --builder cnbs/sample-builder:bionic sample-remote-app
ERROR: failed to build: failed to fetch builder image 'index.docker.io/cnbs/sample-builder:bionic': error during connect: Post "http://dummy%2F/v1.38/images/create?fromImage=cnbs%2Fsample-builder&tag=bionic": http: invalid Host header

After

I managed to connect to a remote daemon and execute the build

> DOCKER_HOST=ssh://[email protected] /Users/jbustamante/go/src/github.com/buildpacks/pack/out/pack build -p ruby-bundler --builder cnbs/sample-builder:bionic sample-remote-app
bionic: Pulling from cnbs/sample-builder
Digest: sha256:1fbc7290c4af32a7803c084aa2e7f0b5a24a22bed6e10701791848d54fd27605
Status: Image is up to date for cnbs/sample-builder:bionic
bionic: Pulling from cnbs/sample-stack-run
Digest: sha256:22f6e78d4f4d541279069a191c27614cb3f935a5a1259e662ca5f22a85d1541a
....

Documentation

• Should this change be documented?
  • Yes, see #___
  • No

Related

Resolves #1870