Don't depend on String8 cast to C string

Bug: 295394788
Test: m checkbuild
Change-Id: I6aa039b6b2a4944e3537ef133f8785890d957edd
diff --git a/libs/androidfw/AssetManager2.cpp b/libs/androidfw/AssetManager2.cpp
index fc9dd14..dc2185ea 100644
--- a/libs/androidfw/AssetManager2.cpp
+++ b/libs/androidfw/AssetManager2.cpp
@@ -897,7 +897,7 @@
 
   log_stream << "\nBest matching is from "
              << (last_resolution_.best_config_name.empty() ? "default"
-                                                   : last_resolution_.best_config_name)
+                    : last_resolution_.best_config_name.c_str())
              << " configuration of " << last_resolution_.best_package_name;
   return log_stream.str();
 }