Deleted profile for compiling with Scala 2.9

Dropping 2.9 support.
`scala.version` property now set in the corresponding profile

Let's have one single place where the `scala.version` is assigned.
This is useful also for the build kitty (which I'm setting up for
validating PRs opened on the scala-refactoring repo).
Deleted `repo.scala-ide` property because it isn't used

This property was used to retrieve the OSGi-fied scala bundles from the
Scala IDE p2 repository. However, in SHA:
8b5efd255fa65dc88710d7d54e7275ce8f225676 we moved the build to use the
plain Scala JARs (because they are already OSGi ready), making the
`repo.scala-ide` effectively unused.