suppress warning stack trace when an intent fails to compile

Change-Id: I04f7c66fb4c24f7db47ba89344bffeaa291f2392
diff --git a/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Compiling.java b/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Compiling.java
index af4153b..ce722f8 100644
--- a/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Compiling.java
+++ b/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Compiling.java
@@ -59,7 +59,7 @@
                     stored.map(IntentData::installables).orElse(null));
             return Optional.of(new Installing(processor, IntentData.compiled(data, compiled), stored));
         } catch (IntentException e) {
-            log.warn("Unable to compile intent {} due to:", data.intent(), e);
+            log.warn("Unable to compile intent {} due to:", data.intent(), e.getMessage());
             if (stored.filter(x -> !x.installables().isEmpty()).isPresent()) {
                 // removing orphaned flows and deallocating resources
                 return Optional.of(new Withdrawing(processor, new IntentData(data, stored.get().installables())));