update_engine: use log_file_path for newer libchrome.

log_file will take a FILE * instead for opened file. To pass a file path
in const char *, log_file_path should be used in newer libchrome.

BUG=chromium:1094927
TEST=emerge update_engine

Change-Id: Ic003f3111b3cfeb2217741c46bf86cdcd543c2a5
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/2434423
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Commit-Queue: Qijiang Fan <fqj@google.com>
Tested-by: Qijiang Fan <fqj@google.com>
diff --git a/logging.cc b/logging.cc
index 6320e36..012feee 100644
--- a/logging.cc
+++ b/logging.cc
@@ -79,7 +79,11 @@
   if (log_to_file) {
     log_file = SetupLogFile(kSystemLogsRoot);
     log_settings.delete_old = logging::APPEND_TO_OLD_LOG_FILE;
+#if BASE_VER < 780000
     log_settings.log_file = log_file.c_str();
+#else
+    log_settings.log_file_path = log_file.c_str();
+#endif
   }
   logging::InitLogging(log_settings);
 }