Several kubectl fixes

[selslack]

SUMMARY

Fixes several bugs which make use of kubectl connection impossible.

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

k8s / kubectl

ANSIBLE VERSION

ansible 2.5.3
  config file = /Users/~~~/ansible/ansible.cfg
  configured module search path = ['/Users/~~~/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /Users/~~~/ansible/env/lib/python3.6/site-packages/ansible
  executable location = /Users/~~~/ansible/env/bin/ansible
  python version = 3.6.4 (default, Mar 20 2018, 23:32:11) [GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.37)]

ADDITIONAL INFORMATION

Fixes these errors when using k8s inventory and kubectl connection:

Typo in inventory parsing:

 [WARNING]:  * Failed to parse /Users/~~~/ansible/inventory/k8s.yml with auto plugin: list indices must be integers or slices, not str
  
  ...
  File "/Users/~~~/ansible/env/lib/python3.6/site-packages/ansible/module_utils/k8s/inventory.py", line 71, in fetch_objects
    namespaces = connections['namespaces']

Absence of --namespace parameter when executing command on pods from non-default namespace:

<~~~> EXEC ['/usr/local/bin/kubectl', 'exec', '-I', '~~~', '-c', '~~~', '--', '/bin/sh', '-c', "/bin/sh -c 'echo ~None && sleep 0'"]

Invalid temp directory (note None):

<~~~> EXEC ['/usr/local/bin/kubectl', '-n', '~~~', 'exec', '-I', '~~~', '-c', '~~~', '--', '/bin/sh', '-c', '/bin/sh -c \'( umask 77 && mkdir -p "` echo ~None/.ansible/tmp/ansible-tmp-1527688125.119122-3174488126227 `" && echo ansible-tmp-1527688125.119122-3174488126227="` echo ~None/.ansible/tmp/ansible-tmp-1527688125.119122-3174488126227 `" ) && sleep 0\'']

[ansibot]

cc @chouseknecht @fabianvf @flaper87 @maxamillion @willthames
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[fabianvf]

shipit

[willthames]

Merged, thanks @selslack