contrib: add specfile
contrib: add OBS submit script
specfile: depend on zeromq-devel

This is compatible with more distributions.
specfile: depend on -devel package

Now that we have a separate package for the valz and valzo binaries,
we must depend on the libvalidator0-devel package to get the
libvalidator.so file.
specfile: make zerovm own /usr/x86_64-nacl directory

This fixes a "directories not owned by a package" error while building
on OBS.
Merge pull request #261 from mgeisler/specfile

specfile: add specfile for RPM builds