[SPARK-1812][wip]

Was just trying out akka 2.3.3 (theoretically it should all work.)
Using ${scala.binary.version} in artifactId gives the following warning in maven:

[WARNING] 
[WARNING] Some problems were encountered while building the effective model for org.apache.spark:spark-core_2.11:jar:1.1.0-SNAPSHOT
[WARNING] 'artifactId' contains an expression but should be a constant. @ org.apache.spark:spark-core_${scala.binary.version}:1.1.0-SNAPSHOT, /Users/avati/work/spark/core/pom.xml, line 29, column 15
[WARNING] 
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] 
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]