`showspikes: true` doesn't work if `showticklabels: false`

[shogun70]

See https://codepen.io/anon/pen/mMvybw

My use case for this is when tick-labels for a "category" axis are too long or too numerous I want to hide the labels and show a bootstrap tooltip at the end of the spikeline. I use hovermode: 'closest' so I don't get the built-in commonLabel on hover.

I'm currently working around this issue using tickfont.color: 'transparent'instead of showticklabels: false.

[etpinard]

Thanks for the report.

Related: #1604

[shogun70]

Thanks, that was fast.

[etpinard]

Thanks for the 10/10 bug report @shogun70 👌