Fix alignment issue in the version command output

[kjagiello]

- What I did
This tiny PR fixes an alignment issue in the version command output.

Before:

$ docker version
Client:
 Version:       18.03.0-ce
 API version:   1.37
 Go version:    go1.9.4
 Git commit:    0520e24
 Built: Wed Mar 21 23:06:22 2018
 OS/Arch:       darwin/amd64
 Experimental:  false
 Orchestrator:  swarm

Server:
 Engine:
  Version:      18.03.0-ce
  API version:  1.37 (minimum version 1.12)
  Go version:   go1.9.4
  Git commit:   0520e24
  Built:        Wed Mar 21 23:14:32 2018
  OS/Arch:      linux/amd64
  Experimental: false

After:

Client:
 Version:       18.04.0-dev
 API version:   1.37
 Go version:    go1.9.4
 Git commit:    241c14d1
 Built:         Mon Mar 26 13:34:21 2018
 OS/Arch:       darwin/amd64
 Experimental:  false
 Orchestrator:  swarm

Server:
 Engine:
  Version:      18.03.0-ce
  API version:  1.37 (minimum version 1.12)
  Go version:   go1.9.4
  Git commit:   0520e24
  Built:        Wed Mar 21 23:14:32 2018
  OS/Arch:      linux/amd64
  Experimental: false

[vdemeester]

hey @kjagiello, thanks for the contribution, but it duplicates #769 😅

[kjagiello]

Oh, how did I miss that? 😄 Closing this one then!

[thaJeztah]

No worries, thanks for working on this!!

I opened #965, which I think should be the right fix, bug awaiting feedback to confirm what the bug was in the tabwriter (perhaps there’s a corner case I’m overlooking)