shill: enable (don't disable) -Wunused

having fixed an unused parameter in the dbus-c++ headers, those
headers no longer have unused parameters. so, if we fix up unused
parameters in shill code, we can compile with -Wunused. (this is
implied by -Wall, as long as we don't override with -Wno-unused.)

BUG=chromium-os:20779
TEST=unittests

- comment out unused parameters in function definitions
- remove some unused local variables
- also: fix an old-style cast

Change-Id: Ie654a7b34d622cecb0f26bd47c17813fe8423001
Reviewed-on: http://gerrit.chromium.org/gerrit/8365
Tested-by: mukesh agrawal <quiche@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
diff --git a/profile_dbus_adaptor.cc b/profile_dbus_adaptor.cc
index bad4e68..13b8f59 100644
--- a/profile_dbus_adaptor.cc
+++ b/profile_dbus_adaptor.cc
@@ -71,13 +71,13 @@
 }
 
 map<string, ::DBus::Variant> ProfileDBusAdaptor::GetEntry(
-    const std::string& name,
-    ::DBus::Error &error) {
+    const std::string& /*name*/,
+    ::DBus::Error &/*error*/) {
   return map<string, ::DBus::Variant>();
 }
 
-void ProfileDBusAdaptor::DeleteEntry(const std::string& name,
-                                     ::DBus::Error &error) {
+void ProfileDBusAdaptor::DeleteEntry(const std::string& /*name*/,
+                                     ::DBus::Error &/*error*/) {
 }
 
 }  // namespace shill