Fix -M/--module-path option for ansible-doc and ansible-console

[fungusakafungus]

SUMMARY

Fixes broken -M/--module-path options of ansible-doc and ansible-console.

Before the change I was getting the following error:

$ ansible-doc -M . raw -s -vvv
ERROR! Unexpected Exception, this is probably a bug: 'list' object has no attribute 'split'
the full traceback was:

Traceback (most recent call last):
  File "/home/user/ansible/ansible/bin/ansible-doc", line 109, in <module>
    exit_code = cli.run()
  File "/home/user/ansible/ansible/lib/ansible/cli/doc.py", line 107, in run
    for i in self.options.module_path.split(os.pathsep):
AttributeError: 'list' object has no attribute 'split'

#29663 changed the logic of the base cli parser, so options.module_path became a list.

I've copied the logic for iterating through options.module_path from the commit that changed it:

ansible/lib/ansible/executor/task_queue_manager.py

Lines 86 to 90 in 2165bac

	# make sure any module paths (if specified) are added to the module_loader
	if options.module_path:
	for path in options.module_path:
	if path:
	module_loader.add_directory(path)

fixes #31743

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

cli/doc, cli/console

ANSIBLE VERSION

ansible 2.5.0 (devel 02cd881697) last updated 2017/10/14 21:11:59 (GMT +200)
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/home/user/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /home/user/ansible/ansible/lib/ansible
  executable location = /home/user/.virtualenvs/ansible/bin/ansible
  python version = 2.7.9 (default, Jun 29 2016, 13:08:31) [GCC 4.9.2]

[alikins]

Looks good to me (LGTM)

[abadger]

cherry-picked for 2.4.1rc2