start writing the #2 version of the format

Summary:
start write the version #2 of the format

the format v2 was introduced a long while ago (more than a month), now new code is everywhere capable of
reading the new format. Let's move on and write the v2 format.

Reviewed By: muirdm

Differential Revision: D58591864

fbshipit-source-id: d86fe4c8521d2cd66cd5f7a905da64f82d1eb204

Author: Liubov Dmitrieva

eden/scm/lib/revisionstore/src/indexedlogauxstore.rs

@@ -45,29 +45,13 @@ pub(crate) type Entry = FileAuxData;
 ///       (v0) also contained content_id hash and blake3 hash was optional,
 ///       also, size field was close to the end, just before the blake3
 pub(crate) fn serialize(this: &FileAuxData, hgid: HgId) -> Result<Bytes> {
-    // Write an original format for the migration period.
-    // version 0
-    let mut buf = Vec::new();
-    buf.write_all(hgid.as_ref())?;
-    buf.write_u8(0)?; // write version
-    buf.write_all(edenapi_types::ContentId::default().as_ref())?;
-    buf.write_all(this.sha1.as_ref())?;
-    buf.write_all(edenapi_types::Sha256::default().as_ref())?;
-    buf.write_vlq(this.total_size)?;
-    buf.write_u8(1)?; // A value of 1 indicates the blake3 hash is present
-    buf.write_all(this.blake3.as_ref())?;
-    Ok(buf.into())
-
-    // TODO(liubovd): finish roll out of the new format after 05-22-2024
-    /* New format (tested)
     let mut buf = Vec::new();
     buf.write_all(hgid.as_ref())?;
     buf.write_u8(2)?; // write version
     buf.write_vlq(this.total_size)?;
     buf.write_all(this.sha1.as_ref())?;
     buf.write_all(this.blake3.as_ref())?;
     Ok(buf.into())
-    */
 }
 
 fn deserialize(bytes: Bytes) -> Result<Option<(HgId, FileAuxData)>> {