[2764] cleanup: removed an unused member function

it was a leftover from an intermediate attempt.

src/lib/util/encode/base_n.cc

@@ -236,7 +236,6 @@ public:
     bool operator==(const DecodeNormalizer& other) const {
         return (base_ == other.base_);
     }
-    bool allDecoded() const { return (base_ == base_end_); }
 private:
     const char base_zero_code_;
     string::const_iterator base_;