Use correct "D-Bus" spelling in rest-api.md

Change "dbus" and "DBUS" to the correct spelling "D-Bus".

Change-Id: I30214d0c2e646857c21010d75f8d1a4560dd2a54
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/rest-api.md b/rest-api.md
index 90e5aaf..72921d4 100644
--- a/rest-api.md
+++ b/rest-api.md
@@ -3,9 +3,9 @@
 The primary management interface for OpenBMC is REST. This document provides
 some basic structure and usage examples for the REST interface.
 
-The schema for the rest interface is directly defined by the OpenBMC dbus
+The schema for the rest interface is directly defined by the OpenBMC D-Bus
 structure. Therefore, the objects, attributes and methods closely map to those
-in the dbus schema.
+in the D-Bus schema.
 
 For a quick explanation of HTTP verbs and how they relate to a RESTful API, see
 <http://www.restapitutorial.com/lessons/httpmethods.html>.
@@ -175,8 +175,8 @@
 
 
 ## HTTP DELETE operations
-DELETE operations are for removing instances. Only DBUS objects (instances) can
-be removed. If the underlying DBUS object implements the
+DELETE operations are for removing instances. Only D-Bus objects (instances) can
+be removed. If the underlying D-Bus object implements the
 `org.openbmc.Object.Delete` interface the REST server will call it. If
 `org.openbmc.Object.Delete` is not implemented, the REST server will return a
 HTTP 403 (Forbidden) error.