[core] Fix an issue in #981 where the newline was missing after printing out (#1084)

the command line, thus leaving the YCSB version on the same line.

(cherry picked from commit 88ffdbbb8f4efd49a710c3602d16cdb9f8b37a14)

core/src/main/java/com/yahoo/ycsb/Client.java

@@ -977,6 +977,7 @@ public final class Client {
     for (String arg : args) {
       System.err.print(" " + arg);
     }
+    System.err.println();
 
     Properties fileprops = new Properties();
     int argindex = 0;