Catch Exceptions, not Throwable to remove blockers found in SonarQube

Change-Id: I49ab731ce0c9950b55063e2afa4ce9226a7b6b4a
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 b49814f..ebc17ca 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
@@ -400,7 +400,7 @@
                             extraneousFlow(rule);
                         }
                     }
-                } catch (Throwable e) {
+                } catch (Exception e) {
                     log.debug("Can't process added or extra rule {}", e.getMessage());
                     continue;
                 }
@@ -409,7 +409,7 @@
                 try {
                     // there are rules in the store that aren't on the switch
                     flowMissing(rule);
-                } catch (Throwable e) {
+                } catch (Exception e) {
                     log.debug("Can't add missing flow rule {}", e.getMessage());
                     continue;
                 }