Revert "Assign by l-value"

This reverts commit 53b95b2.

Author: andreiavrammsd

include/msd/blocking_iterator.hpp

@@ -141,9 +141,10 @@ class blocking_writer_iterator {
      *
      * @return The iterator itself.
      */
-    blocking_writer_iterator& operator=(const value_type& value)
+    template <typename T>
+    blocking_writer_iterator& operator=(T&& value)
     {
-        chan_->write(value);
+        chan_->write(std::forward<T>(value));
         return *this;
     }