cli: Escape non ascii in API call
cli: Escape non ascii in API call

Tester log may contain non ascii characters and json.dumps could
complain:

> UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position
> 7955: ordinal not in range(128)

Signed-off-by: Fam Zheng <df9fd617995bad07eac70e27aa3fe5069270e3bd@redhat.com>

pvital/patchew,pvital/patchew,pvital/patchew,pvital/patchew