[trac893] cleanup: make TSIGKeyRing::find() a const member function

src/lib/dns/tsigkey.cc

@@ -230,7 +230,7 @@ TSIGKeyRing::remove(const Name& key_name) {
 }
 
 TSIGKeyRing::FindResult
-TSIGKeyRing::find(const Name& key_name, const Name& algorithm_name) {
+TSIGKeyRing::find(const Name& key_name, const Name& algorithm_name) const {
     TSIGKeyRingImpl::TSIGKeyMap::const_iterator found =
         impl_->keys.find(key_name);
     if (found == impl_->keys.end() ||

src/lib/dns/tsigkey.h

@@ -322,7 +322,7 @@ public:
     /// \param key_name The name of the key to be found.
     /// \param algorithm_name The name of the algorithm of the found key.
     /// \return A \c FindResult object enclosing the search result (see above).
-    FindResult find(const Name& key_name, const Name& algorithm_name);
+    FindResult find(const Name& key_name, const Name& algorithm_name) const;
 private:
     struct TSIGKeyRingImpl;
     TSIGKeyRingImpl* impl_;