[Bugit] Cannot run bugit on a machine with Nvidia card but the nvidia driver not installed

[Yujin.Wu]

[Summary]
The Bugit cannot on a machine with a Nvidia GPU, but the nvidia related tool doesn't installed.
If run bugit on such machine:

ubuntu@Libra2v1-4:~$ sudo bugit
Traceback (most recent call last):
  File "/snap/bugit/22/bin/bugit", line 33, in <module>
    sys.exit(load_entry_point('bugit==1.1', 'console_scripts', 'bugit')())
  File "/snap/bugit/22/lib/python3.6/site-packages/bugit/__init__.py", line 104, in main
    cid=args.cid,
  File "/snap/bugit/22/lib/python3.6/site-packages/bugit/__init__.py", line 133, in start_ui
    job_output=job_output,
  File "/snap/bugit/22/lib/python3.6/site-packages/bugit/ui.py", line 184, in __init__
    std_info = AttachmentAssistant.get_standard_info()
  File "/snap/bugit/22/lib/python3.6/site-packages/bugit/bug_assistant.py", line 504, in get_standard_info
    command, stdout=subprocess.PIPE, stderr=subprocess.PIPE
  File "/snap/bugit/22/usr/lib/python3.6/subprocess.py", line 423, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/snap/bugit/22/usr/lib/python3.6/subprocess.py", line 729, in __init__
    restore_signals, start_new_session)
  File "/snap/bugit/22/usr/lib/python3.6/subprocess.py", line 1364, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'nvidia-smi': 'nvidia-smi'

[Steps to reproduce]
Install bugit on the machine with Nvidia GPU, then remove nvdia-smi, then run bugit.

[Expected result]
The bugit should can be run on such machine even if the nvida-smi not installed.

[Actual result]
The Bugit cannot run and report exception.

[Failure rate]
100%