Clarify and add more details to some log messages

Change-Id: I3b9df11748e41e857ed0bc3e166d1434743902de
diff --git a/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java b/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
index 9357138..a2c0299 100644
--- a/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
+++ b/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
@@ -534,7 +534,8 @@
                         }
                     }
                 } catch (Exception e) {
-                    log.warn("Can't process added or extra rule {}", e);
+                    log.warn("Can't process added or extra rule {} for device {}:{}",
+                             rule, deviceId, e);
                 }
             }