Remove unused method

biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/gatk/CommandLineGATK.scala

@@ -418,11 +418,3 @@ trait CommandLineGATK extends BiopetJavaCommandLineFunction with Reference with
     optional("-l", logging_level, spaceSeparated = true, escape = true, format = "%s") +
     optional("-log", log_to_file, spaceSeparated = true, escape = true, format = "%s")
 }
-
-object CommandLineGATK {
-
-  def isFileWithTag(file: File, tag: String): Boolean = file match {
-    case f:TaggedFile => f.tag == tag
-    case _ => false
-  }
-}
\ No newline at end of file