JSON should be UTF-8 encoded before being passed to HTTP::Request

[shattered]

Otherwise, "HTTP::Message content must be bytes at .../Google/API/Method.pm line 42." exception while trying to set a Google Drive file's description to something non-Latin-1.

[shattered]

See also liskin@31eaa29

[liskin]

(Worth noting that not all credit is mine, I wanted to use https://github.com/TakeAsh/google-api-perl-client/commits/utf8 but the commits were all mixed up so I just took the relevant bits... :-))