REST: Return a 405 on bad DELETE paths

Return a method_not_allowed response when the path for a
DELETE is invalid.  This matches what the phosphor-rest
server did.

Change-Id: I6db577d25d92bdbee9e97355ff11a15a5c68288b
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/include/openbmc_dbus_rest.hpp b/include/openbmc_dbus_rest.hpp
index e310b1a..5a00572 100644
--- a/include/openbmc_dbus_rest.hpp
+++ b/include/openbmc_dbus_rest.hpp
@@ -1480,8 +1480,9 @@
             if (ec || interfaceNames.size() <= 0)
             {
                 BMCWEB_LOG_ERROR << "Can't find object";
-                setErrorResponse(res, boost::beast::http::status::not_found,
-                                 notFoundDesc, notFoundMsg);
+                setErrorResponse(res,
+                                 boost::beast::http::status::method_not_allowed,
+                                 methodNotAllowedDesc, methodNotAllowedMsg);
                 res.end();
                 return;
             }