utils: Add a class to cache service lookups

Currently we are doing interface + path -> service lookups for each ipmi
command sent to the daemon. For many types of commands this is not ideal
as the daemon is unlikely to change often at runtime. Implement a basic
cache with the ability to invalidate the service name at any time. This
is used by code in a future commit.

Change-Id: I85b04dd17ac19e31d49070f289704b429bd1e577
Signed-off-by: William A. Kennington III <wak@google.com>
2 files changed