Executing expand.py from outer dir

[haruyama480]

expand.py could fail when execution from outer directory.

% python3 ${HOME}/src/github.com/rust-lang-ja/ac-library-rs/expand.py segtree
Traceback (most recent call last):
  File "xxxxxxx/src/github.com/rust-lang-ja/ac-library-rs/expand.py", line 99, in <module>
    buf = output_file(i)
  File "xxxxxxx/src/github.com/rust-lang-ja/ac-library-rs/expand.py", line 53, in output_file
    with open(src_path+filename+'.rs', 'r') as f:
FileNotFoundError: [Errno 2] No such file or directory: 'src/internal_bit.rs'

It can be solved with reference of argv[0]

[TonalidadeHidrica]

Expanders do not affect language update; triaged as low priority.

[haruyama480]

I'm sorry for late response. I fixed conflicts!

[TonalidadeHidrica]

@haruyama480 Thanks for fixing, I'm reviewing when I have a time. By the way did you pushed the last commit 2d270b8 by mistake?