Delete slasher schema v4

slasher/src/database.rs

@@ -25,7 +25,7 @@ use types::{
 };
 
 /// Current database schema version, to check compatibility of on-disk DB with software.
-pub const CURRENT_SCHEMA_VERSION: u64 = 4;
+pub const CURRENT_SCHEMA_VERSION: u64 = 3;
 
 /// Metadata about the slashing database itself.
 const METADATA_DB: &str = "metadata";

slasher/src/migrate.rs

@@ -17,10 +17,6 @@ impl<E: EthSpec> SlasherDB<E> {
                     software_schema_version: CURRENT_SCHEMA_VERSION,
                 }),
                 (x, y) if x == y => Ok(self),
-                (3, 4) => {
-                    // TODO(electra): db migration due to `IndexedAttestationOnDisk`
-                    Ok(self)
-                }
                 (_, _) => Err(Error::IncompatibleSchemaVersion {
                     database_schema_version: schema_version,
                     software_schema_version: CURRENT_SCHEMA_VERSION,