Flow path cannot be removed when it goes through a non-existing ISL
**Steps:**
given: A busy environment with reroutes happening. An ISL with flows going though it
1. Call port down on one end of ISL
2. As soon as isl is marked as FAILED delete the ISL using NB API
3. Check existing flow paths. Repeat above steps until you get a flow path that still use the removed ISL
**Problem:** Flow leaves excess flow paths during reroutes due to following errors
```
Flow perfload_28Feb133820_640_onion6002 error - CompleteFlowPathRemovalAction failed: ISL 00:00:b2:81:f7:c9:1f:55_4 - 00:00:cc:2e:48:4f:a9:6c_2 not found to be updated
```
```
Flow perfload_28Feb133820_640_onion6002 error - Failed to remove paths : Failed to remove paths: "perfload_28Feb133820_640_onion6002_31b20347-2fab-4fe8-8b06-43ab00cf9b27", "perfload_28Feb133820_640_onion6002_103977e2-f365-430b-b622-a313a859bcde"
```
diff --git a/src-java/flowhs-topology/flowhs-storm-topology/src/main/java/org/openkilda/wfm/topology/flowhs/fsm/common/actions/BaseFlowPathRemovalAction.java b/src-java/flowhs-topology/flowhs-storm-topology/src/main/java/org/openkilda/wfm/topology/flowhs/fsm/common/actions/BaseFlowPathRemovalAction.java
index db6f7ba2f..25215eb92 100644
--- a/src-java/flowhs-topology/flowhs-storm-topology/src/main/java/org/openkilda/wfm/topology/flowhs/fsm/common/actions/BaseFlowPathRemovalAction.java
+++ b/src-java/flowhs-topology/flowhs-storm-topology/src/main/java/org/openkilda/wfm/topology/flowhs/fsm/common/actions/BaseFlowPathRemovalAction.java
@@ -20,6 +20,7 @@ import static java.lang.String.format;
 import org.openkilda.model.Flow;
 import org.openkilda.model.FlowPath;
 import org.openkilda.model.SwitchId;
+import org.openkilda.persistence.PersistenceException;
 import org.openkilda.persistence.PersistenceManager;
 import org.openkilda.persistence.repositories.IslRepository;
 import org.openkilda.wfm.share.history.model.FlowDumpData;
@@ -73,7 +74,12 @@ public abstract class BaseFlowPathRemovalAction<T extends FlowProcessingFsm<T, S
                 dstSwitch, dstPort);
         log.debug("Updating ISL {}_{} - {}_{} with used bandwidth {}", srcSwitch, srcPort, dstSwitch, dstPort,
                 usedBandwidth);
-        islRepository.updateAvailableBandwidth(srcSwitch, srcPort, dstSwitch, dstPort, usedBandwidth);
+        try {
+            islRepository.updateAvailableBandwidth(srcSwitch, srcPort, dstSwitch, dstPort, usedBandwidth);
+        } catch (PersistenceException e) {
+            log.warn(format("Couldn't update ISL %s_%d - %s_%d with used bandwidth %d. %s",
+                    srcSwitch, srcPort, dstSwitch, dstPort, usedBandwidth, e.getMessage()), e);
+        }
     }
 
     protected void saveRemovalActionWithDumpToHistory(T stateMachine, Flow flow, FlowPath flowPath) {
['src-java/flowhs-topology/flowhs-storm-topology/src/main/java/org/openkilda/wfm/topology/flowhs/fsm/common/actions/BaseFlowPathRemovalAction.java']