Fixed bug where no default editor broke CommandConfig

[skovhus]

Just a small bug fix. Replaced the rather unknown fallback editor "editor" with good old "nano".

[gpmidi]

This fixes an issue that a friend was having where he would get an OSError because his base OS, CentOS 6 from a minimal install, doesn't have 'editor' installed.

This pull request will resolve this issue for CentOS/RHEL users as well as help those users who aren't familiar with VIM.

Traceback (most recent call last):
  File "/usr/bin/mark2", line 6, in <module>
    sys.exit(main())
  File "/usr/mark2/mk2/launcher.py", line 605, in main
    command.start()
  File "/usr/mark2/mk2/launcher.py", line 126, in start
    self.run()
  File "/usr/mark2/mk2/launcher.py", line 479, in run
    subprocess.call([editor, path_tmp])
  File "/usr/lib64/python2.6/subprocess.py", line 478, in call
    p = Popen(*popenargs, **kwargs)
  File "/usr/lib64/python2.6/subprocess.py", line 642, in __init__
    errread, errwrite)
  File "/usr/lib64/python2.6/subprocess.py", line 1234, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

[prophile]

It strikes me that assuming nano is installed is as big an assumption as assuming editor is installed.

Perhaps vi as an alternative, since its installation is required by POSIX?

[gpmidi]

Very good point. VI probably is the safest option.

[jwflory]

I can confirm that I am also having this issue. This would solve many of the frustrations in getting it working on RHEL-based distros.

Also worth noting, as told to me by the #mcdevs IRC channel, my CentOS box doesn't have 'vi' installed as a default in CentOS 6.5. I only have 'vim', which is more or less the same thing, but just the "improved" version. Found in /usr/bin/vim