Correctly update the blast fiels before the goto not after !!!

This commit was SVN r4304.

src/datatype/dt_pack.c

@@ -367,6 +367,7 @@ int ompi_convertor_pack_no_conversion( ompi_convertor_t* pConv,
                     iov[iov_pos].iov_len -= space_on_iovec;
                     last_count = 0;
                     pos_desc = -1;
+                    last_blength = 0;
                     goto end_loop;
                 }
                 pConv->stack_pos--;
@@ -466,8 +467,8 @@ int ompi_convertor_pack_no_conversion( ompi_convertor_t* pConv,
                             bConverted += saveLength;
                             space -= saveLength;
                             saveLength = last_blength;
-                            if( ++iov_pos == (*out_size) ) goto end_loop;
                             last_blength = 0;
+                            if( ++iov_pos == (*out_size) ) goto end_loop;
                             pDestBuf = iov[iov_pos].iov_base;
                             space_on_iovec = iov[iov_pos].iov_len;
                             break;