This tests "ipsec rsasigkey" functionality.

This tests stock functionality of generating a single key that is 
randomly chosen in size, using the --vary option.

The random device is a file, since UMLs have poor randomness, and
repeatability is important.

devrandom.bin created with:
      dd if=/dev/random ibs=1 obs=512 count=3072 of=devrandom.bin

