rename requesterState to RequestContext

Change-Id: I747559b4da11b350b01494c7c54a674c3d3d45f9
diff --git a/src/requester-state.hpp b/src/requester-state.hpp
index a6f1028..3f6bba9 100644
--- a/src/requester-state.hpp
+++ b/src/requester-state.hpp
@@ -29,9 +29,9 @@
 namespace ndncert {
 namespace requester {
 
-struct RequesterState {
+struct RequestContext {
   explicit
-  RequesterState(security::KeyChain& keyChain, const CaProfile& caItem, RequestType requestType);
+  RequestContext(security::KeyChain& keyChain, const CaProfile& caItem, RequestType requestType);
 
   /**
    * @brief The CA profile for this request.