Dashboard rendering error on Dual Axis line chart

[kkalyan]

Make sure these boxes are checked before submitting your issue - thank you!

• I have checked the superset logs for python stacktraces and included it here as text if any
• I have reproduced the issue with at least the latest released version of superset
• I have checked the issue tracker for the same issue and I haven't found one similar

Superset version

{"GIT_SHA": "f905726c24b1d1f65a55b38592cb51c0f45deb15", "version": "0.23.0dev"}

Steps to reproduce

Create a dashboard with two dual axis line charts.
One of them renders fine, other slice and rest of the dashboard does not work.

Actual results

on Refresh (random slice has the error)

nvd3_vis.js:556 Uncaught TypeError: chart.xScale is not a function
    at Object.drawGraph [as generate] (nvd3_vis.js:556)
    at renderLoop (nv.d3.js:99)

@Mogball

[Mogball]

nv.models.multiChart which is used for the Dual Axis Line Chart does not expose xScale in the latest release 1.8.6, although there is novus/nvd3@2dd8024.

[mistercrunch]

Merged related PR