Fix regex for scala-compiler jar (and friends)

Running gatling was failing for me because of the final '-' in the regex to find the scala-library.jar. Here's my classpath:

[debug] 	$HOME/.sbt/boot/scala-2.10.+/lib/scala-library.jar
[debug] 	$HOME/.sbt/boot/scala-2.10.+/lib/scala-compiler.jar