Loosen permissions on /etc/docker directory
Loosen permissions on /etc/docker directory

The `/etc/docker` directory is used both by the dockerd daemon
and the docker cli (if installed on the saem host as the daemon).

In situations where the `/etc/docker` directory does not exist,
and an initial `key.json` (legacy trust key) is generated (at the
default location), the `/etc/docker/` directory was created with
0700 permissions, making the directory only accessible by `root`.

Given that the `0600` permissions on the key itself already protect
it from being used by other users, the permissions of `/etc/docker`
can be less restrictive.

This patch changes the permissions for the directory to `0755`, so
that the CLI (if executed as non-root) can also access this directory.

> **NOTE**: "strictly", this patch is only needed for situations where no _custom_
> location for the trustkey is specified (not overridden with `--deprecated-key-path`),
> but setting the permissions only for the "default" case would make
> this more complicated.

```bash
make binary shell

make install

ls -la /etc/ | grep docker

dockerd
^C

ls -la /etc/ | grep docker
drwxr-xr-x 2 root root    4096 Sep 14 12:11 docker
```

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

YuPengZTE/docker,rremer/moby,pradipd/moby,paralin/docker,moul/docker,djs55/docker,konstruktoid/docker-1,thaJeztah/docker,crosbymichael/docker,Mokolea/docker,vdemeester/docker,bearstech/moby,flavio/docker,jvanz/docker,bearstech/moby,jwhonce/docker,gnailuy/docker,yongtang/docker,dims/docker,vdemeester/docker,jimjag/docker,rremer/moby,KarthikNayak/docker,docker/docker,x1022as/docker,jimjag/docker,jlhawn/docker,thaJeztah/docker,kolyshkin/docker,paralin/docker,jwhonce/docker,Mokolea/docker,kolyshkin/moby,kojiromike/docker,laijs/docker,scotttlin/docker,laijs/moby,nalind/docker,maxamillion/docker,tmp6154/docker,yongtang/docker,jwhonce/docker,yosifkit/docker,nawawi/docker,rremer/moby,KarthikNayak/docker,gnailuy/docker,kolyshkin/moby,mikebrow/docker,cpuguy83/docker,pradipd/moby,jlhawn/docker,vdemeester/docker,ibuildthecloud/docker,justincormack/docker,flavio/docker,trebonian/docker,jameszhan/docker,dims/docker,mahak/docker,AkihiroSuda/docker,paralin/docker,laijs/docker,Ramzec/docker,jthelin/docker,nawawi/docker,jvanz/docker,justincormack/docker,laijs/docker,jameszhan/docker,docker/docker,jameszhan/docker,SvenDowideit/docker,rancher/docker,flavio/docker,crosbymichael/docker,nawawi/docker,estesp/docker,moby/moby,scotttlin/docker,moby/moby,konstruktoid/docker-upstream,scotttlin/docker,flavio/docker,rancher/docker,crosbymichael/docker,djs55/docker,yosifkit/docker,mahak/docker,jthelin/docker,moby/moby,dmcgowan/docker,yosifkit/docker,docker/docker,dims/docker,konstruktoid/docker-upstream,nalind/docker,kojiromike/docker,kojiromike/docker,tmp6154/docker,ibuildthecloud/docker,kolyshkin/docker,bearstech/moby,estesp/docker,jlhawn/docker,djs55/docker,YuPengZTE/docker,moby/moby,YuPengZTE/docker,thaJeztah/docker,ibuildthecloud/docker,ibuildthecloud/docker,moul/docker,mikebrow/docker,gnailuy/docker,cpuguy83/docker,gnailuy/docker,jvanz/docker,Ramzec/docker,yosifkit/docker,kolyshkin/moby,nalind/docker,moul/docker,trebonian/docker,unclejack/docker,mahak/docker,nalind/docker,Ramzec/docker,mikebrow/docker,jimjag/docker,trebonian/docker,laijs/moby,rancher/docker,konstruktoid/docker-1,konstruktoid/docker-1,unclejack/docker,maxamillion/docker,moul/docker,jimjag/docker,x1022as/docker,cpuguy83/docker,SvenDowideit/docker,AkihiroSuda/docker,dmcgowan/docker,AkihiroSuda/docker,dmcgowan/docker,bearstech/moby,tmp6154/docker,pradipd/moby,maxamillion/docker,konstruktoid/docker-upstream,AkihiroSuda/docker,x1022as/docker,SvenDowideit/docker,Mokolea/docker,trebonian/docker,mahak/docker,Mokolea/docker,yongtang/docker,konstruktoid/docker-upstream,cpuguy83/docker,estesp/docker,nawawi/docker,paralin/docker,unclejack/docker,laijs/moby,thaJeztah/docker,ibuildthecloud/docker,justincormack/docker,Ramzec/docker,KarthikNayak/docker