In python3, strings are unicode by default. We need to encode/decode
from command pipelines and other places where we interface with the
real world using the correct locales. This patch updates various
call sites to use the correct encoding/decodings.
(From OE-Core rev: bb4685af1bffe17b3aa92a6d21398f38a44ea874)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>