use namespace for ca and rename CaState to ca::RequestState

Change-Id: I2250bf7fb68503465dae18e16dc3c512fe809037
diff --git a/src/identity-challenge/challenge-module.hpp b/src/identity-challenge/challenge-module.hpp
index 22c6a4c..f1c942f 100644
--- a/src/identity-challenge/challenge-module.hpp
+++ b/src/identity-challenge/challenge-module.hpp
@@ -51,7 +51,7 @@
 
   // For CA
   virtual std::tuple<ErrorCode, std::string>
-  handleChallengeRequest(const Block& params, CaState& request) = 0;
+  handleChallengeRequest(const Block& params, ca::RequestState& request) = 0;
 
   // For Client
   virtual std::vector<std::tuple<std::string, std::string>>
@@ -68,14 +68,14 @@
 protected:
   // used by challenge modules
   std::tuple<ErrorCode, std::string>
-  returnWithError(CaState& request, ErrorCode errorCode, std::string&& errorInfo);
+  returnWithError(ca::RequestState& request, ErrorCode errorCode, std::string&& errorInfo);
 
   std::tuple<ErrorCode, std::string>
-  returnWithNewChallengeStatus(CaState& request, const std::string& challengeStatus,
+  returnWithNewChallengeStatus(ca::RequestState& request, const std::string& challengeStatus,
                                JsonSection&& challengeSecret, size_t remainingTries, time::seconds remainingTime);
 
   std::tuple<ErrorCode, std::string>
-  returnWithSuccess(CaState& request);
+  returnWithSuccess(ca::RequestState& request);
 
 public:
   const std::string CHALLENGE_TYPE;