graph/db: remove unused Wipe method

Later on we will create an interface for the persisted graph data. We
want this interface to be as small and as neat as possible. In
preparation for this, we remove this unused `Wipe` method.

graph/db/kv_store.go

@@ -299,29 +299,6 @@ var graphTopLevelBuckets = [][]byte{
 	closedScidBucket,
 }
 
-// Wipe completely deletes all saved state within all used buckets within the
-// database. The deletion is done in a single transaction, therefore this
-// operation is fully atomic.
-func (c *KVStore) Wipe() error {
-	err := kvdb.Update(c.db, func(tx kvdb.RwTx) error {
-		for _, tlb := range graphTopLevelBuckets {
-			err := tx.DeleteTopLevelBucket(tlb)
-			if err != nil &&
-				!errors.Is(err, kvdb.ErrBucketNotFound) {
-
-				return err
-			}
-		}
-
-		return nil
-	}, func() {})
-	if err != nil {
-		return err
-	}
-
-	return initKVStore(c.db)
-}
-
 // createChannelDB creates and initializes a fresh version of  In
 // the case that the target path has not yet been created or doesn't yet exist,
 // then the path is created. Additionally, all required top-level buckets used