rename headers to match style

Moving headers from ".h" to ".hpp"

Reworked the header inclusion a bit so that host-ipmid is treated as a
library, and local headers aren't.

renamed apphandler.h => apphandler.hpp
renamed chassishandler.h => chassishandler.hpp
renamed globalhandler.h => globalhandler.hpp
renamed sensorhandler.h => sensorhandler.hpp
renamed storageaddsel.h => storageaddsel.hpp
renamed storagehandler.h => storagehandler.hpp
renamed systemintfcmds.h => systemintfcmds.hpp

Change-Id: I9d4ce3dd57e2e996800f9020a10cc10cdf2c3914
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/app/watchdog.cpp b/app/watchdog.cpp
index f6818cb..3d8e227 100644
--- a/app/watchdog.cpp
+++ b/app/watchdog.cpp
@@ -4,6 +4,7 @@
 #include "watchdog_service.hpp"
 
 #include <endian.h>
+#include <host-ipmid/ipmid-api.h>
 
 #include <cstdint>
 #include <phosphor-logging/elog-errors.hpp>
@@ -12,8 +13,6 @@
 #include <string>
 #include <xyz/openbmc_project/Common/error.hpp>
 
-#include "host-ipmid/ipmid-api.h"
-
 using phosphor::logging::commit;
 using phosphor::logging::level;
 using phosphor::logging::log;