buildman: Translate more strings to latin-1

When writing out some of our results we may now have UTF-8 characters
in there as well.  Translate these to latin-1 and ignore any errors (as
this is for diagnostic and given the githash anything else can be
reconstructed by the user.
Reviewed-by: NSimon Glass <sjg@chromium.org>
Signed-off-by: NTom Rini <trini@konsulko.com>

tools/buildman/builderthread.py

@@ -280,13 +280,13 @@ class BuilderThread(threading.Thread):
         outfile = os.path.join(build_dir, 'log')
         with open(outfile, 'w') as fd:
             if result.stdout:
-                fd.write(result.stdout)
+                fd.write(result.stdout.encode('latin-1', 'ignore'))
 
         errfile = self.builder.GetErrFile(result.commit_upto,
                 result.brd.target)
         if result.stderr:
             with open(errfile, 'w') as fd:
-                fd.write(result.stderr)
+                fd.write(result.stderr.encode('latin-1', 'ignore'))
         elif os.path.exists(errfile):
             os.remove(errfile)