"smap" is now the appropriate data structure for a string-to-string map.
Also changes ovsdb_datum_from_shash() into ovsdb_datum_from_smap() since
system-stats related code was the only client.
Signed-off-by: Ben Pfaff <blp@nicira.com>
A smap is a string to string hash map. It has a cleaner interface
than shash's which were traditionally used for the same purpose.
This patch implements the data structure, and changes netdev and
its providers to use it.
Signed-off-by: Ethan Jackson <ethan@nicira.com>
