fixed some `go vet` issues.
using `errors.New` instead `fmt.Error`.
Updated and simplified the PG example
fixed `Looback` typo.
add env variable to disable kernel version warning

Allow the user to set DOCKER_NOWARN_KERNEL_VERSION=1 to disable the
warning for RHEL 6.5 and other distributions that don't exhibit the
panics described in https://github.com/dotcloud/docker/issues/407.
Added myself to docs MAINTAINERS
Merge pull request #2993 from jpoimboe/rhel6-version-check

remove kernel version warning on rhel 6.5
Merge pull request #3031 from jamtur01/docsmaintain

Add James Turnbull to docs maintainers
Merge pull request #2966 from andrewsmedina/govet2

fixed some `go vet` issues.
Merge branch 'pgdoc' of github.com:jamtur01/docker into 2971-test

Conflicts:
	docs/sources/examples/postgresql_service.rst
Merge branch '2971-test'