message registry: Remove odata.context

Redfish made odata.context optional (1.6.0 of DSP0266) and
has removed odata.context from example payloads in the
specification (1.7.0 of DSP0266), removed it from the mockups,
and Redfish recommended not using.

This removes the last odata.type.

Tested: Built this commit and the commits below and loaded on a
        Witherspoon. No validator errors.
Change-Id: I4cff07b9196f7e9461ea49bb8bcc706e3945e033
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/redfish-core/lib/message_registries.hpp b/redfish-core/lib/message_registries.hpp
index 96ce0c2..628c63a 100644
--- a/redfish-core/lib/message_registries.hpp
+++ b/redfish-core/lib/message_registries.hpp
@@ -52,9 +52,6 @@
         res.jsonValue = {
             {"@odata.type",
              "#MessageRegistryFileCollection.MessageRegistryFileCollection"},
-            {"@odata.context", "/redfish/v1/"
-                               "$metadata#MessageRegistryFileCollection."
-                               "MessageRegistryFileCollection"},
             {"@odata.id", "/redfish/v1/Registries"},
             {"Name", "MessageRegistryFile Collection"},
             {"Description", "Collection of MessageRegistryFiles"},
@@ -90,8 +87,6 @@
         res.jsonValue = {
             {"@odata.id", "/redfish/v1/Registries/Base"},
             {"@odata.type", "#MessageRegistryFile.v1_1_0.MessageRegistryFile"},
-            {"@odata.context",
-             "/redfish/v1/$metadata#MessageRegistryFile.MessageRegistryFile"},
             {"Name", "Base Message Registry File"},
             {"Description", "DMTF Base Message Registry File Location"},
             {"Id", message_registries::base::header.registryPrefix},
@@ -192,8 +187,6 @@
         res.jsonValue = {
             {"@odata.id", "/redfish/v1/Registries/OpenBMC"},
             {"@odata.type", "#MessageRegistryFile.v1_1_0.MessageRegistryFile"},
-            {"@odata.context",
-             "/redfish/v1/$metadata#MessageRegistryFile.MessageRegistryFile"},
             {"Name", "Open BMC Message Registry File"},
             {"Description", "Open BMC Message Registry File Location"},
             {"Id", message_registries::openbmc::header.registryPrefix},