Only include ipmid/api.hpp for the new API

After some feedback from users of the new IPMI API, they wanted to see
two things:
 1) don't require ipmid/api.hpp and ipmid/registration.hpp to be able to
    write new handlers
 2) only require including ipmid/api.hpp (instead of ipmid/api.h)

So now, by simply including ipmid/api.hpp instead of ipmid/api.h
(deprecated), handlers incorporating the new IPMI API can be written.

Change-Id: I446dcce70cff03d4ecc28c658292d052485f77fc
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
diff --git a/app/watchdog_service.cpp b/app/watchdog_service.cpp
index e65ea63..284964d 100644
--- a/app/watchdog_service.cpp
+++ b/app/watchdog_service.cpp
@@ -1,8 +1,7 @@
 #include "watchdog_service.hpp"
 
-#include <ipmid/api.h>
-
 #include <exception>
+#include <ipmid/api.hpp>
 #include <phosphor-logging/elog-errors.hpp>
 #include <phosphor-logging/elog.hpp>
 #include <phosphor-logging/log.hpp>