Modify UnicodeDecodeError

Hi.
I fixed UnicodeEncodeError when I try search with unicode strings like 싸이.
```Python
from apiclient.discovery import build

youtube = build(YOUTUBE_API_SERVICE_NAME, YOUTUBE_API_VERSION, developerKey=DEVELOPER_KEY)

youtube.search().list(
    q="싸이",
    part="id,snippet",
    maxResults=25
).execute()
```
I done tested for few languages(Korean, Japanese, Arabic).

Thank you.