Change how update_engine_client handles DBus proxy failures.

Change GetProxy() to log failures with LOG(ERROR) and then
terminate, rather than use LOG(FATAL), as the latter unhelpfully
generates a core file.

BUG=chromium-os:37542
TEST=run update_engine_client with and without a working update_engine

Change-Id: Id84b56ff0b5ffa51cf4fda4cb7ad847f5bb617e5
Reviewed-on: https://gerrit.chromium.org/gerrit/41662
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Richard Barnette <jrbarnette@chromium.org>
diff --git a/update_engine_client.cc b/update_engine_client.cc
index 9d5767c..1f3dc34 100644
--- a/update_engine_client.cc
+++ b/update_engine_client.cc
@@ -45,7 +45,10 @@
   const int kRetrySeconds = 10;
 
   bus = dbus_g_bus_get(DBUS_BUS_SYSTEM, &error);
-  LOG_IF(FATAL, !bus) << "Failed to get bus: " << GetAndFreeGError(&error);
+  if (bus == NULL) {
+    LOG(ERROR) << "Failed to get bus: " << GetAndFreeGError(&error);
+    exit(1);
+  }
   for (int i = 0; !proxy && i < kTries; ++i) {
     if (i > 0) {
       LOG(INFO) << "Retrying to get dbus proxy. Try "
@@ -61,8 +64,11 @@
                             << kUpdateEngineServiceName << ": "
                             << GetAndFreeGError(&error);
   }
-  LOG_IF(FATAL, !proxy) << "Giving up -- unable to get dbus proxy for "
-                        << kUpdateEngineServiceName;
+  if (proxy == NULL) {
+    LOG(ERROR) << "Giving up -- unable to get dbus proxy for "
+               << kUpdateEngineServiceName;
+    exit(1);
+  }
   *out_proxy = proxy;
   return true;
 }