fix bug 1055268 - Package Socorro

Adds the ability to package an *rpm* of Socorro while not disrupting *tarball* creation.

This can be done in bash by
```bash
$ export BUILD_TYPE=rpm
$ socorro/scripts/build.sh
```

There is also a `make` target for package, but like the install target, it will not work without first exporting environment variables.
This is actually slightly wrong, as the rpm that will get generated has the git-tag as it's version and in the name. So `socorro.x86_64.rpm` is really `socorro-$GITTAG-$EPOCH.x86_64.rpm`. Having a repo would make this simple.

We could either generate them without a version & epoch, or give Jenkins a post-build process to rename the rpm.