classes/lib: Update to use python3 command pipeline decoding

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>

meta/classes/chrpath.bbclass

@@ -10,6 +10,8 @@ def process_file_linux(cmd, fpath, rootdir, baseprefix, tmpdir, d):
     if p.returncode != 0:
         return
 
+    err = err.decode('utf-8')
+
     # Handle RUNPATH as well as RPATH
     err = err.replace("RUNPATH=","RPATH=")
     # Throw away everything other than the rpath list