Fix ByteBuf leak

Signed-off-by: Graham <gpe@openrs2.org>

archive/src/main/kotlin/org/openrs2/archive/cache/CacheImporter.kt

@@ -102,11 +102,11 @@ public class CacheImporter @Inject constructor(
 
             // import master index
             val masterIndex = createMasterIndex(store)
-            if (masterIndex.index.entries.isEmpty()) {
-                throw IOException("Master index empty, cache probably corrupt")
-            }
-
             val masterIndexId = try {
+                if (masterIndex.index.entries.isEmpty()) {
+                    throw IOException("Master index empty, cache probably corrupt")
+                }
+
                 addMasterIndex(connection, masterIndex)
             } finally {
                 masterIndex.release()