Fix preference dialog breaking issue

[ZhennanWu]

Origin: https://bugs.gentoo.org/905906

Problem

When trying to open the preference for Chinese-Pinyin in ibus-setup, an error is thrown:

Traceback (most recent call last):
  File "/usr/share/ibus-pinyin/setup/main.py", line 432, in <module>
    main()
  File "/usr/share/ibus-pinyin/setup/main.py", line 428, in main
    PreferencesDialog(name).run()
    ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/share/ibus-pinyin/setup/main.py", line 48, in __init__
    gettext.bind_textdomain_codeset("ibus-pinyin", "UTF-8")
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'gettext' has no attribute 'bind_textdomain_codeset'

Cause

The relevant APIs were already removed in Python 3.10:
https://bugs.python.org/issue40936
https://docs.python.org/3.10/library/gettext.html#gettext.bind_textdomain_codeset

This is a UX issue but does prevent basic functionalities.

Using python >=3.10 will raise this problem.

Potential Fix

By removing this single line seems to fix the issue. The preference can now function properly

File "/usr/share/ibus-pinyin/setup/main.py", line 48, in __init__
    gettext.bind_textdomain_codeset("ibus-pinyin", "UTF-8")

No further usages of removed API were found.

Disclaimer

I haven't performed deeper testing to see if the removal of this line will cause problem elsewhere

[epico]

Please consider the following code:

DOMAINNAME = 'ibus-pinyin'

# Python's gettext module doesn't provide all methods in
# new Python version
try:
    gettext.bindtextdomain(DOMAINNAME, localedir)
    gettext.bind_textdomain_codeset(DOMAINNAME, 'UTF-8')
except AttributeError:
    pass

[epico]

Please squash the two commits into one commit, thanks!

[ZhennanWu]

@epico The commits are now squashed

[epico]

Thanks for the patch!