Fix incorrect use of [[fallthrough]]

fix #468

CHANGELOG.md

@@ -7,6 +7,7 @@ Version 54:
 * basic_fields members and coverage
 * Add string_param
 * Retain ownership when reading using a message
+* Fix incorrect use of [[fallthrough]]
 
 API Changes:
 

include/beast/http/impl/read.ipp

@@ -140,7 +140,6 @@ operator()(error_code ec, std::size_t bytes_transferred)
         if(! ec || ec != http::error::need_more)
             goto do_upcall;
         ec = {};
-        BOOST_FALLTHROUGH;
 
     do_read:
         try
@@ -277,7 +276,6 @@ operator()(error_code ec)
                 bind_handler(std::move(*this), ec));
         }
         state_ = 2;
-        BOOST_FALLTHROUGH;
 
     do_read:
         return async_read_some(