This appears to be broken for me as well.
In the main pom.xml I don't see any assembly descriptor.
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-assembly-plugin:2.2-beta-5:assembly (default-cli) on project org.springframework.roo.root: Error reading assemblies: No assembly descriptors found. -> [Help 1]
I was able to get a packaged roo bundle that I could use with STS by going into deployment-support
./roo-deploy.sh -c assembly -tv
It failed on GPG detatched signature creation - but I don't care about that since I just wanted the bundle... which then resides at the top level source directory under target/roo-deploy/work/(version name)
There might be an easier way to get it to build and to get a sts-usable version of the roo tools from the top level using only maven, but I don't know how