Tweak syntastic task to print a raw classpath.

Having a raw classpath is useful if you're running something via the
`java` command.

For example:

```
java -cp $(buildr -s classpath)
-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=8010
org.junit.runner.JUnitCore org.candlepin.model.test.OwnerTest
```