Improve exclusion file reader error messages.

jplag/src/main/java/jplag/JPlag.java

@@ -438,16 +438,16 @@ public class JPlag implements ProgramI {
         excludedFileNames = new HashSet<>();
 
         try {
-            BufferedReader in = new BufferedReader(new FileReader(options.getExclusionFileName()));
+            BufferedReader reader = new BufferedReader(new FileReader(options.getExclusionFileName()));
             String line;
 
-            while ((line = in.readLine()) != null) {
+            while ((line = reader.readLine()) != null) {
                 excludedFileNames.add(line.trim());
             }
 
-            in.close();
-        } catch (IOException e) {
-            System.out.println("Could not read exclusion file: " + options.getExclusionFileName());
+            reader.close();
+        } catch (IOException exception) {
+            System.out.println("Could not read exclusion file: "+ exception.getMessage());
         }
 
         if (options.getVerbosity() == LONG) {