safekeeper: Fix a log message of HTTP worker (#9213)

## Problem
There is a wrong log message.

## Summary of changes
Fixed the log message.

safekeeper/src/lib.rs

@@ -161,7 +161,7 @@ pub static HTTP_RUNTIME: Lazy<Runtime> = Lazy::new(|| {
         .thread_name("HTTP worker")
         .enable_all()
         .build()
-        .expect("Failed to create WAL service runtime")
+        .expect("Failed to create HTTP runtime")
 });
 
 pub static BROKER_RUNTIME: Lazy<Runtime> = Lazy::new(|| {