In ssh_checkintr(), better check pointers for NULL before they are dereferenced.
In ssh_checkintr(), better check pointers for NULL before they
are dereferenced.

XXX Looks like there are duplicated sections in this function. This
driver needs a huge cleanup anyway...

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars