Update error that results when snapshot is missing (#24839)

ledger/src/bank_forks_utils.rs

@@ -104,7 +104,10 @@ pub fn load_bank_forks(
         {
             true
         } else {
-            info!("No snapshot package available; will load from genesis");
+            warn!(
+                "No snapshot package found in directory: {:?}; will load from genesis",
+                &snapshot_config.full_snapshot_archives_dir
+            );
             false
         }
     } else {

ledger/src/blockstore_processor.rs

@@ -1114,7 +1114,7 @@ fn process_bank_0(
         None,
         &mut ExecuteTimings::default(),
     )
-    .expect("processing for bank 0 must succeed");
+    .expect("Failed to process bank 0 from ledger. Did you forget to provide a snapshot?");
     bank0.freeze();
     if blockstore.is_primary_access() {
         blockstore.insert_bank_hash(bank0.slot(), bank0.hash(), false);