This adds a patch from Debian, as they're already have security modules from NSS
in it's own library directory rather than /usr/lib{,64}/ and patch in loading of
libsoftokn as well.
The patch and our own fix of the patch (well, they hardcode Debian specific
stuff in there) ensures that SECMOD_AddNewModule() will find the right module
from the derivation's output path, so the built-in CA root certificates are
recognized and verified correctly.
