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/groupext.cpp b/groupext.cpp
index dbfade4..5b71dde 100644
--- a/groupext.cpp
+++ b/groupext.cpp
@@ -1,6 +1,5 @@
-#include <ipmid/api.h>
-
 #include <cstdio>
+#include <ipmid/api.hpp>
 
 #define GRPEXT_GET_GROUP_CMD 0
 void register_netfn_groupext_functions() __attribute__((constructor));