rpc/server: Remove unnecessary check for nil namespace.
rpc/server: Remove unnecessary check for nil namespace.

Change-Id: I88865e8cbd998b2943f127c51266fa9436d0034e

vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref