DEV: Less verbose remapping

It's hard to see which columns have been remapped when remapping prints
lots of "0 rows affected" lines. This changes it to output the row count
only for affected columns.

lib/remap.rb

@@ -49,7 +49,7 @@ WHERE table_schema='public' and (data_type like 'char%' or data_type like 'text%
             AND #{column_name} <> replace(#{column_name}, $1, $2)", [@from, @to])
       end
 
-      log "#{result.cmd_tuples} rows affected!"
+      log "#{result.cmd_tuples} rows affected!" if result.cmd_tuples > 0
     end
 
     Theme.expire_site_cache!