bitbake: bitbake: Convert to python 3

Various misc changes to convert bitbake to python3 which don't warrant
separation into separate commits.

(Bitbake rev: d0f904d407f57998419bd9c305ce53e5eaa36b24)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/tests/parse.py

@@ -50,7 +50,7 @@ C = "3"
     def parsehelper(self, content, suffix = ".bb"):
 
         f = tempfile.NamedTemporaryFile(suffix = suffix)
-        f.write(content)
+        f.write(bytes(content, "utf-8"))
         f.flush()
         os.chdir(os.path.dirname(f.name))
         return f