Fix encoding of cc_cmd
Fix encoding of cc_cmd

The cc we've got so far is a list of unicode strings, but here the
output is raw string (byte array). The following union operation
shouldn't mix these two types. Explicitly decode it like in
popen_lines().

Reported-by: Peter Xu <c223ca75e606f6d9c295be0e3c74321a96fe6cd7@redhat.com>
Signed-off-by: Fam Zheng <df9fd617995bad07eac70e27aa3fe5069270e3bd@redhat.com>

stefanha/git-publish,stefanha/git-publish