Fix SBT dependencies information

With double '%' SBT tries to find the dependencies compiled with the
locally used Scala version[1]. Since most Maven projects doesn't use
Scala this results in errors like:

[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn] :: UNRESOLVED DEPENDENCIES ::
[warn] ::::::::::::::::::::::::::::::::::::::::::::::
[warn] :: joda-time#joda-time_2.10;2.3: not found
[warn] ::::::::::::::::::::::::::::::::::::::::::::::

[1] http://www.scala-sbt.org/release/docs/Library-Management.html#Dependencies