Suppress warning about obsolete function custom-show

* lisp/cus-edit.el (custom-variable-value-create): Suppress
warning about obsolete function custom-show.  The widget this
supports has been obsolete since Emacs 24, but we should perhaps
be very conservative about removing widget types, so suppress the
warning instead of removing the widget type.
1 job for master in 3 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #2123
test-all

00:00:03

 
Name Stage Failure
failed
test-all Test There has been a runner system failure, please try again
Running with gitlab-runner 11.6.0 (f100a208)
on gitlab-runner-docker cff9d373
Using Docker executor with image debian:stretch ...
Pulling docker image debian:stretch ...
Using docker image sha256:e1de74e67cc70422153600785c4ce4c29843a0e59e18b634c52ca133c564437f for debian:stretch ...
ERROR: Job failed (system failure): Error response from daemon: failed to start shim: exec: "docker-containerd-shim": executable file not found in $PATH: unknown (executor_docker.go:1018:0s)