SLF4JLog: Fix debug log level

The debug method was logging at info level.

Change-Id: I622974b6c3eb2c9d579f920290771b67a8322479
diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/peers/jgroups/SLF4JLog.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/peers/jgroups/SLF4JLog.java
index 98716af..43b6f9c 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/peers/jgroups/SLF4JLog.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/peers/jgroups/SLF4JLog.java
@@ -125,7 +125,7 @@
 
   @Override
   public void debug(String msg) {
-    logger.info(msg);
+    logger.debug(msg);
   }
 
   @Override