network_manager_main: Make sure errors sync to journal

Otherwise we get no info and can't debug.

Change-Id: I28ed63148cf0643a9df8917a5a059fc6c31487a8
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/network_manager_main.cpp b/src/network_manager_main.cpp
index 1c2e38e..ffd97df 100644
--- a/src/network_manager_main.cpp
+++ b/src/network_manager_main.cpp
@@ -320,8 +320,8 @@
     }
     catch (const std::exception& e)
     {
-        auto msg = fmt::format("FAILED: {}", e.what());
-        log<level::ERR>(msg.c_str(), entry("ERROR", e.what()));
+        fmt::print(stderr, "FAILED: {}", e.what());
+        fflush(stderr);
         return 1;
     }
 }