Remove empty constructs

flexiprep/src/main/scala/nl/lumc/sasc/biopet/pipelines/flexiprep/Cutadapt.scala

@@ -38,7 +38,7 @@ class Cutadapt(root: Configurable, fastqc: Fastqc) extends nl.lumc.sasc.biopet.e
       (fastqc.foundAdapters ++ customAdapters)
         .map(adapter => adapter.seq -> adapter.name).toMap
     } else {
-      Map.empty ++ customAdapters.map(adapter => adapter.seq -> adapter.name).toMap
+      customAdapters.map(adapter => adapter.seq -> adapter.name).toMap
     }
   }
 

flexiprep/src/main/scala/nl/lumc/sasc/biopet/pipelines/flexiprep/QcCommand.scala

@@ -107,7 +107,7 @@ class QcCommand(val root: Configurable, val fastqc: Fastqc) extends BiopetComman
       val foundAdapters = if (!cutadapt.ignoreFastqcAdapters) {
         fastqc.foundAdapters.map(_.seq) ++ cutadapt.customAdapters.map(_.seq)
       } else {
-        Seq.empty ++ cutadapt.customAdapters.map(_.seq)
+        cutadapt.customAdapters.map(_.seq)
       }
 
       if (foundAdapters.nonEmpty) {