Switch to euimage for image distribution

Rather than compressing and tarring up the image, we instead switch to
using the tech preview of euimage-pack-image from euca2ools 3.2 to
distribute images.  This, in concert with the new
euca-install-service-image command in eucalyptus 4.1, should make
installing and configuring Eucalyptus service images significantly
easier.

I probably broke build-rpm.sh here, in no small part because I intend to
have Jenkins auto-increment version numbers as necessary.  Sorry.