revert: rollback AHashMap changes and keep using std HashMap (#6741)

* Revert "perf(ecstore): use AHashMap for FileInfo metadata fields (#6738)"

This reverts commit 13a2ae212e.

* fix(filemeta): restore standard HashMap metadata (#6742)

Remove the direct ahash dependency added for FileInfo metadata and revert the affected filemeta/ecstore call sites back to std::collections::HashMap.

Co-authored-by: heihutu <heihutu@gmail.com>

---------

Co-authored-by: heihutu <heihutu@gmail.com>

crates/ecstore/src/services/rebalance/migration.rs

@@ -57,7 +57,7 @@ fn rebalance_remote_tiered_opts(
         versioned: version_id.is_some(),
         version_id,
         mod_time: version.mod_time,
-        user_defined: version.metadata.iter().map(|(k, v)| (k.clone(), v.clone())).collect(),
+        user_defined: version.metadata.clone(),
         src_pool_idx,
         data_movement: true,
         include_part_checksums: true,

crates/ecstore/src/services/tier/tier.rs

@@ -1454,9 +1454,7 @@ fn tier_backend_identity(config: &TierConfig) -> io::Result<TierDestinationId> {
     encode_tier_backend_identity(tier_type, endpoint, bucket, prefix, region, routing_account)
 }
 
-pub(crate) fn tier_destination_id_from_metadata<S: std::hash::BuildHasher>(
-    metadata: &HashMap<String, String, S>,
-) -> io::Result<Option<TierDestinationId>> {
+pub(crate) fn tier_destination_id_from_metadata(metadata: &HashMap<String, String>) -> io::Result<Option<TierDestinationId>> {
     let Some(encoded) = rustfs_utils::http::metadata_compat::get_consistent_str(
         metadata,
         rustfs_utils::http::metadata_compat::SUFFIX_TRANSITION_TIER_DESTINATION_ID,