Don't log on cache hit.

src/library.rs

@@ -300,10 +300,7 @@ impl Library {
         let db = self.cache_db.clone();
         match db.get(key.as_bytes()) {
             // Cache hit, return bytes as-is.
-            Ok(Some(bytes)) => {
-                info!("cache HIT {}", key);
-                Some(bytes)
-            }
+            Ok(Some(bytes)) => Some(bytes),
             // Cache miss, fill cache and return.
             Ok(None) => {
                 info!("cache MISS {}", key);