docker: fixup redepends and clean rsuggests

With the 5.0 kernel and docker 18.09 you can run into issues
pulling from docker hub due to an invalid/unknown certificate.
We fix that by adding ca-certifcates as a runtime dependency.

There can also be isuses setting up the network bridge, so we
add bridge-utils to the rdepends.

We also add some comments about this recipe and how it should
be updated using moby (and why it is like it is).

Finally, no one wants rt-tests and lxc when installing docker,
so we drop them from the rsuggests.

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

recipes-containers/docker/docker_git.bb

@@ -9,8 +9,8 @@ DESCRIPTION = "Linux container runtime \
  large-scale web deployments, database clusters, continuous deployment \
  systems, private PaaS, service-oriented architectures, etc. \
  . \
- This package contains the daemon and client. Using docker.io is \
- officially supported on x86_64 and arm (32-bit) hosts. \
+ This package contains the daemon and client, which are \
+ officially supported on x86_64 and arm hosts. \
  Other architectures are considered experimental. \
  . \
  Also, note that kernel version 3.10 or above is required for proper \
@@ -18,6 +18,22 @@ DESCRIPTION = "Linux container runtime \
  subtle and/or glaring issues. \
  "
 
+# Notes:
+#   - This docker variant uses moby and the other individually maintained
+#     upstream variants for SRCREVs
+#   - It is a true community / upstream tracking build, and is not a
+#     docker curated set of commits or additions
+#   - The version number on this package tracks the versions assigned to
+#     the curated docker-ce repository. This allows compatibility and
+#     functional equivalence, while allowing new features to be more
+#     easily added.
+#   - This could be called "docker-moby" or just "moby" in the future, but
+#     that would require the creation of a virtual/docker dependency, which
+#     is possible, but overkill at the moment (while we wait for the upstream
+#     to stop changing).
+#   - The common components of this recipe and docker-ce do need to be moved
+#     to a docker.inc recipe
+
 # moby commit matches the docker-ce swarmkit bump on the 18.09 branch
 SRCREV_moby = "667e800b2cf920c6d3d7c32fdbc5811934d99769"
 SRCREV_libnetwork = "4725f2163fb214a6312f3beae5991f838ec36326"
@@ -71,11 +87,12 @@ DEPENDS_append_class-target = " lvm2"
 RDEPENDS_${PN} = "util-linux util-linux-unshare iptables \
                   ${@bb.utils.contains('DISTRO_FEATURES', 'aufs', 'aufs-util', '', d)} \
                   ${@bb.utils.contains('DISTRO_FEATURES', 'systemd', '', 'cgroup-lite', d)} \
+                  bridge-utils \
+                  ca-certificates \
                  "
 RDEPENDS_${PN} += "virtual/containerd virtual/runc"
 
 RRECOMMENDS_${PN} = "kernel-module-dm-thin-pool kernel-module-nf-nat docker-init"
-RSUGGESTS_${PN} = "lxc rt-tests"
 DOCKER_PKG="github.com/docker/docker"
 
 inherit systemd update-rc.d