dispatch_conf: don't pass bytes for Popen cmd

This will fix bug #410417.
diff --git a/pym/portage/dispatch_conf.py b/pym/portage/dispatch_conf.py
index cc98fad..c81153a 100644
--- a/pym/portage/dispatch_conf.py
+++ b/pym/portage/dispatch_conf.py
@@ -30,7 +30,7 @@
     """
     # Use Popen to emulate getstatusoutput(), since getstatusoutput() may
     # raise a UnicodeDecodeError which makes the output inaccessible.
-    proc = subprocess.Popen(portage._unicode_encode(cmd % (file1, file2)),
+    proc = subprocess.Popen(cmd % (file1, file2),
         stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell=True)
     output = portage._unicode_decode(proc.communicate()[0])
     if output and output[-1] == "\n":