shill: log values of flags as hex, rather than decimal

wetware processes base16->base2 conversion more rapidly and more
accurately than base10->base2 conversions.

BUG=None
TEST=manual+autotest

this CL also adds logging statements to DeviceInfo::DelLinkMsgHandler
and DeviceInfo::RemoveInfo. DeviceInfo previously only logged on link
insertion, not link deletion.

Change-Id: Iaa29db6dd4ad21e711800d8268e22fd10946f158
Reviewed-on: http://gerrit.chromium.org/gerrit/6678
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Tested-by: mukesh agrawal <quiche@chromium.org>
diff --git a/device_info.cc b/device_info.cc
index c7afe61..d147ae9 100644
--- a/device_info.cc
+++ b/device_info.cc
@@ -144,7 +144,9 @@
   unsigned int flags = msg.link_status().flags;
   unsigned int change = msg.link_status().change;
   VLOG(2) << __func__ << "(index=" << dev_index
-          << ", flags=" << flags << ", change=" << change << ")";
+          << std::showbase << std::hex
+          << ", flags=" << flags << ", change=" << change << ")"
+          << std::dec << std::noshowbase;
   infos_[dev_index].flags = flags;
 
   DeviceRefPtr device = GetDevice(dev_index);
@@ -198,6 +200,8 @@
 }
 
 void DeviceInfo::DelLinkMsgHandler(const RTNLMessage &msg) {
+  VLOG(2) << __func__ << "(index=" << msg.interface_index() << ")";
+
   DCHECK(msg.type() == RTNLMessage::kMessageTypeLink &&
          msg.mode() == RTNLMessage::kMessageModeDelete);
   RemoveInfo(msg.interface_index());
@@ -242,6 +246,8 @@
       manager_->DeregisterDevice(iter->second.device);
     }
     infos_.erase(iter);
+  } else {
+    VLOG(2) << __func__ << "unknown device index: " << interface_index;
   }
 }