Fix a typo in the tutorial
docs/installation/google: update gcloud options

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
Merge pull request #7112 from proppy/patch-8

docs/installation/google: update gcloud options
Merge pull request #7134 from MidnightDesign/patch-1

Fix a typo in the tutorial
pkg/units: Increased test coverage. Closes #7159.

Increased coverage:

  * Added test cases to size_test.go
  * Added coverage for duration.go

Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)
Add missing error check

Docker-DCO-1.1-Signed-off-by: Nathan LeClaire <nathan.leclaire@docker.com> (github: nathanleclaire)
Merge pull request #7160 from fcarriedo/7159-test-coverage

pkg/units: Increased test coverage
Merge pull request #7162 from nathanleclaire/tar-with-options-err-check

Add missing error check
pkg/units: Better to not use `error` as var name

Better to not use `error` as var name (might eclipse the error type) for
clarity and to prevent subtle bugs.

Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)