Replace include guards with #pragma once

Change-Id: I16adc78d397e3239440206e8e70ebbd5e0963adb
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/sensorcache.hpp b/sensorcache.hpp
index 02405ff..6e8c4f1 100644
--- a/sensorcache.hpp
+++ b/sensorcache.hpp
@@ -1,5 +1,4 @@
-#ifndef __SENSORCACHE_H
-#define __SENSORCACHE_H
+#pragma once
 
 #include <map>
 
@@ -27,6 +26,4 @@
         container_t container;
 };
 
-#endif
-
 // vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4