1139888 - Document the default for validate.

We had documented the incorrect default for an importer's validate
setting. This commit corrects the documentation.

https://bugzilla.redhat.com/show_bug.cgi?id=1139888
Merge branch '1139888' into 2.4-release
Merge branch '2.4-dev' into 2.5-testing
Merge branch '2.5-testing' into 2.5-dev