Change message_registries namespace to registries

The message_registries namespace is overly wordy, and results in very
long defines.  Doing this one minor change reduces the code by 50 lines.
This seems worthwhile.

Tested: Unit tests pass.  Namespace change only.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Ib1401580b3fa47596eb56cdc86e60eeeb1c2f952
diff --git a/scripts/parse_registries.py b/scripts/parse_registries.py
index a8b50bf..63dcbca 100755
--- a/scripts/parse_registries.py
+++ b/scripts/parse_registries.py
@@ -30,7 +30,7 @@
 
 // clang-format off
 
-namespace redfish::message_registries::{}
+namespace redfish::registries::{}
 {{
 '''
 
@@ -142,7 +142,7 @@
                 "    {} = {},\n".format(messageId, index))
         registry.write(
             "}};\n"
-            "}} // namespace redfish::message_registries::{}\n"
+            "}} // namespace redfish::registries::{}\n"
             .format(namespace))