Revert "Removed debugging code"

This reverts commit c15bf48f77.

I did not test this well enough, sorry! This introduced problems
such as interactive shell not working anymore (#40), cryptsetup partion
creating not working anymore etc.

pmb/helpers/run.py

@@ -65,7 +65,7 @@ def _execute(loop, args, cmd, log_message, log, return_stdout, check=True):
     transport.close()
 
     return_code = transport.get_returncode()
-    if return_code != 0:
+    if return_code != 0 and False:
         if check:
             raise RuntimeError("Command failed: \n" + protocol.error)
     args.logfd.write('Program exited with: {}\n'.format(transport.get_returncode()))