add space in log message

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1898395 13f79535-47bb-0310-9956-ffa450edef68

poi/src/main/java/org/apache/poi/util/XMLHelper.java

 
     private static void logThrowable(Throwable t, String message, String name) {
         if (System.currentTimeMillis() > lastLog + TimeUnit.MINUTES.toMillis(5)) {
-            LOG.atWarn().withThrowable(t).log("{} [log suppressed for 5 minutes]{}", message, name);
+            LOG.atWarn().withThrowable(t).log("{} [log suppressed for 5 minutes] {}", message, name);
             lastLog = System.currentTimeMillis();
         }
     }