Confusing prompt in directory backend storage directory config

[Dewey_Oxberger]

This is common during an install:

If you config the backend and create a new storage group and assign it to a directory that has not been created yet you'll see somthing like this:

Path /some/place/new doesn't exist.

Do you want to fix the problems?

Yes, fix them now. No, I know what I'm doing.

I keep expecting "Yes, fix them now" to create the directory for me.

Perhaps this should be something like:

Path /some/place/new doesn't exist.

Do you want to go back and choose a directory that exists?

Yes, go back and choose another directory. No, I will make the directory myself.

[cpinkham]

(In [21387]) Fix a bug in the exit prompt of mythtv-setup which could get the plurality wrong in the error message. Also update the error message to be a little clearer about the fact that the user has to fix the problems, mythtv-setup will not do that automatically just because the user selects 'Yes please" when mythtv-setup asks if they want to fix the problems.

Closes #6239.

I didn't run lrelease to regenerate the .qm files for this one minor change, but I did update the .ts so that translators will not be forced to retranslate.