Properly ignore the last argument if there are an odd number.

When we saw the problem, I thought "there's no way!" because
the Logger is hardened and battle-tested.

But no. Since depot no longer depends on samskivert, it has
reimplemented Logger and throws away a lot of the goodness that
has evolved over the years. Goodness like:
- warning if there are an odd number of args and the last one
  isn't a Throwable.
- catching problems toString()ing any of the objects in the message.

Let's go ride a fixie.

src/main/java/com/samskivert/depot/Log.java

@@ -45,7 +45,7 @@ public class Log
         if (args.length < 2) return message;
         StringBuilder sb = new StringBuilder(message);
         sb.append(" [");
-        for (int ii = 0; ii < args.length; ii += 2) {
+        for (int ii = 0, nn = args.length - (args.length % 2); ii < nn; ii += 2) {
             sb.append(args[ii]).append("=").append(args[ii+1]);
         }
         return sb.append("]").toString();