shill: improve logging

- add logging of D-Bus interactions
- convert some error->Populate calls to Error::PopulateAndLog
- slipped in: some whitespace and spelling fixes

BUG=chromium-os:29882
TEST=unit tests

Change-Id: I29cd455cb74cbf467e978a6dc7db3cadac248e43
Reviewed-on: https://gerrit.chromium.org/gerrit/21383
Commit-Ready: mukesh agrawal <quiche@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Tested-by: mukesh agrawal <quiche@chromium.org>
diff --git a/dbus_objectmanager_proxy.cc b/dbus_objectmanager_proxy.cc
index eab79e5..e3146c1 100644
--- a/dbus_objectmanager_proxy.cc
+++ b/dbus_objectmanager_proxy.cc
@@ -5,8 +5,8 @@
 
 #include <base/logging.h>
 
-#include "cellular_error.h"
-#include "scope_logger.h"
+#include "shill/cellular_error.h"
+#include "shill/scope_logger.h"
 
 using std::string;
 
@@ -25,6 +25,7 @@
     int timeout) {
   scoped_ptr<ManagedObjectsCallback> cb(new ManagedObjectsCallback(callback));
   try {
+    SLOG(DBus, 2) << __func__;
     proxy_.GetManagedObjects(cb.get(), timeout);
     cb.release();
   } catch (DBus::Error e) {