[1688] (unrelated cleanup) make RESERVE_RRSETS a private member of Query class.

This will prevent it from causing definition bloat even if the linkder
doesn't combine the constant def.  It would also make more sense to make
it inaccessible from others anyway, because it's basically an
implementation-internal constatnt.

src/bin/auth/query.h

@@ -37,13 +37,6 @@ class DataSourceClient;
 
 namespace auth {
 
-/// \brief Initial reserved size for the vectors in Query
-///
-/// The value is larger than we expect the vectors to even become, and
-/// has been chosen arbitrarily. The reason to set them quite high is
-/// to prevent reallocation on addition.
-const size_t RESERVE_RRSETS = 64;
-
 /// The \c Query class represents a standard DNS query that encapsulates
 /// processing logic to answer the query.
 ///
@@ -76,6 +69,12 @@ const size_t RESERVE_RRSETS = 64;
 /// we keep this name at the moment.
 class Query : boost::noncopyable {
 private:
+    /// \brief Initial reserved size for the vectors in Query
+    ///
+    /// The value is larger than we expect the vectors to even become, and
+    /// has been chosen arbitrarily. The reason to set them quite high is
+    /// to prevent reallocation on addition.
+    static const size_t RESERVE_RRSETS = 64;
 
     /// \brief Adds a SOA.
     ///