skipVerify is not passed to command vars

If kapacitor is https enabled and is using self-signed certificate, `vars` command will always fail. Because it seems `skipVerify` option is not passed to command `vars`

https://github.com/influxdata/kapacitor/blob/1574f6a72e5088cfb728d0e03cbcc5686f324707/cmd/kapacitor/main.go#L2265

Not a major issue though, as a workaround, just curl-ing to URL from error with `-k` option will work.

Start at cmd/kapacitor/main.go around line 2265, where the vars command is defined, and trace how skipVerify is handled for Kapacitor's HTTPS connection. Ensure the vars command receives the option when using a self-signed certificate, then verify that the command works with certificate verification skipped.

Written by the indexing model from the issue text.