Don't swallow exception

Author: nicktindall

modules/repository-azure/src/main/java/org/elasticsearch/repositories/azure/AzureBlobStore.java

@@ -319,7 +319,7 @@ private void deleteListOfBlobs(AzureBlobServiceClient azureBlobServiceClient, It
                 }
             }
         } catch (Exception e) {
-            throw new IOException("Unable to delete blobs");
+            throw new IOException("Unable to delete blobs", e);
         }
     }