Bump up version number of .aria2 control file to 0001.
New aria2 can still load version 0000 file but it saves the file
in
version 0001 format. It means that new aria2 can resume download
started by old aria2 but the opposite is not true.
* src/DefaultBtProgressInfoFile.cc
* src/DefaultBtProgressInfoFile.h
* test/DefaultBtProgressInfoFileTest.cc