mutation_reader: shard_reader: get rid of stop

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>

mutation_reader.cc

@@ -1627,8 +1627,6 @@ public:
     shard_reader(const shard_reader&) = delete;
     shard_reader& operator=(const shard_reader&) = delete;
 
-    void stop() noexcept;
-
     const mutation_fragment& peek_buffer() const {
         return buffer().front();
     }
@@ -1646,12 +1644,6 @@ public:
     }
 };
 
-// FIXME: get rid of stop once we make sure
-// shard_reader is always closed before destruction
-void shard_reader::stop() noexcept {
-    (void)close();
-}
-
 future<> shard_reader::close() noexcept {
     // Nothing to do if there was no reader created, nor is there a background
     // read ahead in progress which will create one.