implement Delete operation

accounts/pkg/indexer/index/disk/autoincrement.go

@@ -263,5 +263,5 @@ func (idx *Autoincrement) next() (int, error) {
 
 // Delete deletes the index folder from its storage.
 func (idx *Autoincrement) Delete() error {
-	return nil
+	return os.Remove(idx.indexRootDir)
 }

accounts/pkg/indexer/index/disk/helper.go

@@ -0,0 +1 @@
+package disk

accounts/pkg/indexer/index/disk/non_unique.go

@@ -236,5 +236,5 @@ func (idx *NonUnique) FilesDir() string {
 
 // Delete deletes the index folder from its storage.
 func (idx *NonUnique) Delete() error {
-	return nil
+	return os.Remove(idx.indexRootDir)
 }

accounts/pkg/indexer/index/disk/unique.go

@@ -223,5 +223,5 @@ func isValidSymlink(path string) (err error) {
 
 // Delete deletes the index folder from its storage.
 func (idx *Unique) Delete() error {
-	return nil
+	return os.Remove(idx.indexRootDir)
 }