Fix broken gallery examples

[bjlittle]

We need to investigate and fix the broken gallery example for 2.2.0 https://scitools.org.uk/iris/docs/latest/examples/General/coriolis_plot.html#coriolis-plot-01-00

Why didn't the automated graphics test identify this as a failure? 🙀

[bjlittle]

BTW This works at 2.1.0 https://scitools.org.uk/iris/docs/v2.1/examples/General/coriolis_plot.html#coriolis-plot-01-00

[bjlittle]

Appears to be related to how the built docs are pushed live - see https://scitools-docs.github.io/iris/master/index.html

Should we add this link back in to the README.md

[lbdreyer]

See PR that fixes the coriolis plot here: SciTools/scitools.org.uk#229

[lbdreyer]

SciTools/scitools.org.uk#229 has been merged so this can be closed !

[lbdreyer]

Appears to be related to how the built docs are pushed live - see https://scitools-docs.github.io/iris/master/index.html

Should we add this link back in to the README.md

This seems to be a different issue so I have created a new issue to handle this: #3396