Fix regression when using importorskip at module level

[nicoddemus]

Fix #1822

cc @jaraco

[coveralls]

Coverage increased (+0.004%) to 93.019% when pulling 63dc71c on nicoddemus:importorskip-regression into 3a200b7 on pytest-dev:master.

[The-Compiler]

Thanks for the quick fix!

[jaraco]

Yes. Thanks for the quick fix.

[nicoddemus]

I plan to release 3.0.1 on monday if no serious regression comes up until then.