Fix various logging related issues.
diff --git a/src/main/java/net/onrc/onos/graph/GraphDBConnection.java b/src/main/java/net/onrc/onos/graph/GraphDBConnection.java
index 7938bb6..16869c5 100644
--- a/src/main/java/net/onrc/onos/graph/GraphDBConnection.java
+++ b/src/main/java/net/onrc/onos/graph/GraphDBConnection.java
@@ -167,7 +167,7 @@
 		try {
 			commit();
 		} catch (Exception e) {
-			log.error("{}", e.toString());
+			log.error("close() failed with exception", e);
 		}
 	}
 }