[1177] Comment update

DNSSEC/NSEC order looks awkward.

src/lib/datasrc/database.h

@@ -476,7 +476,7 @@ public:
     virtual const std::string& getDBName() const = 0;
 
     /**
-     * \brief It returns the previous name in DNSSEC/NSEC order.
+     * \brief It returns the previous name in DNSSEC order.
      *
      * This is used in DatabaseClient::findPreviousName and does more
      * or less the real work, except for working on strings.

src/lib/datasrc/zone.h

@@ -211,7 +211,7 @@ public:
 
     /// \brief Get previous name in the zone
     ///
-    /// Gets the previous name in the DNSSEC/NSEC order. This can be used
+    /// Gets the previous name in the DNSSEC order. This can be used
     /// to find the correct NSEC records for proving nonexistence
     /// of domains.
     ///