`cinder-rtstool save` results in "IOError: [Errno 2] No such file or directory: '/etc/target/saveconfig.json.temp'"

Issue

When applying the fix described in Cinder iSCSI target configuration lost on target.service restart or host reboot the step cinder-rtstool save results in the following trace:

# cinder-rtstool save 

Traceback (most recent call last):
  File "/usr/bin/cinder-rtstool", line 234, in <module>
    sys.exit(main())
  File "/usr/bin/cinder-rtstool", line 225, in main
    save_to_file(destination_file)
  File "/usr/bin/cinder-rtstool", line 160, in save_to_file
    rtsroot.save_to_file(destination_file)
  File "/usr/lib/python2.7/site-packages/rtslib/root.py", line 235, in save_to_file
    with open(save_file+".temp", "w+") as f:
IOError: [Errno 2] No such file or directory: '/etc/target/saveconfig.json.temp'