ethernet: Remove unused SendHostNameEnabled property

Remove EthernetInterfaceData.SendHostNameEnabled as it is defined but
never used excepting reading it from DBus.

Tested:
Build pass.

Change-Id: Ib64792b5842a1e8fb95e3a38d40f11797cfb5641
Signed-off-by: Jiaqing Zhao <jiaqing.zhao@intel.com>
diff --git a/redfish-core/lib/ethernet.hpp b/redfish-core/lib/ethernet.hpp
index 3b2ae75..7986c6f 100644
--- a/redfish-core/lib/ethernet.hpp
+++ b/redfish-core/lib/ethernet.hpp
@@ -83,7 +83,6 @@
     bool DNSEnabled;
     bool NTPEnabled;
     bool HostNameEnabled;
-    bool SendHostNameEnabled;
     bool linkUp;
     bool nicEnabled;
     std::string DHCPEnabled;
@@ -391,16 +390,6 @@
                                 ethData.HostNameEnabled = *hostNameEnabled;
                             }
                         }
-                        else if (propertyPair.first == "SendHostNameEnabled")
-                        {
-                            const bool* sendHostNameEnabled =
-                                std::get_if<bool>(&propertyPair.second);
-                            if (sendHostNameEnabled != nullptr)
-                            {
-                                ethData.SendHostNameEnabled =
-                                    *sendHostNameEnabled;
-                            }
-                        }
                     }
                 }
             }