DeviceMapper: Succeed immediately when removing non-existant devices

We've seen situations where removal of "ID-init" failed during
container deletion (EBUSY), after removal of "ID" has succeeded. This
caused the container delete operation to fail, and on the next delete
attempt the removal of "ID" failed immediately with "does not exist".

Ideally we should not fail the ID-init removal, but its also non-ideal
to allow a state where the container is half-removed and we cannot
make progress deleting the container. So, we silently ignore not-exist
errors on device removal.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
spelling correction

s/singal/signal/

Docker-DCO-1.1-Signed-off-by: Dolph Mathews <dolph.mathews@gmail.com> (github: dolph)
Update email + add self to pkg/signal

Docker-DCO-1.1-Signed-off-by: Guillaume J. Charmes <guillaume@charmes.net> (github: creack)
Like signal_linux.go, we don't have import os and os/signal

Docker-DCO-1.1-Signed-off-by: Kato Kazuyoshi <kato.kazuyoshi@gmail.com> (github: kzys)
Move execdriver construction into execdriver/execdrivers

This can't be in execdriver (dependency loop) but should not be
hardcoded inside runtime.go either. So we put it in a subpackage.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Merge pull request #4583 from kzys/freebsd-signal

Like signal_linux.go, we don't have import os and os/signal
Merge pull request #4569 from dolph/master

spelling correction
Merge pull request #4499 from alexlarsson/fix-remove-fail

DeviceMapper: Succeed immediately when removing non-existant devices
Add deprecation warning for -t on pull

Closes #3410
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge pull request #4466 from alexlarsson/execdrivers

Move execdriver construction into execdriver/execdrivers
Merge pull request #4589 from creack/update_maintainer

Update MAINTAINER email + add self to pkg/signal MAINTAINER
Merge pull request #4491 from crosbymichael/add-pull-dep

Add deprecation warning for -t on pull
support for `docker run` environment variables file

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
pkg/opts: Close the file handle

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
--env-file instead of --envfile

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
go fmt

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
Fixing doc references to --env-file

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
make the --env-file accept multiple flags

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
env-file: update functionality and docs

Multiple flags allowed. Order prescribed. Examples provided. Multiline
accounted for.

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
env-file: remove the unneeded deprecation markup

Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)