Fix crontab argument order for writing

[AMDmi3]

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

cron module

ANSIBLE VERSION

ansible 2.0.2.0
  config file = /home/amdmi3/.ansible.cfg
  configured module search path = Default w/o overrides

SUMMARY

Currently, when writing user's crontab, ansible calls

crontab <file> -u <user>

This is incorrect according to crontab(1) on both FreeBSD and Linux,
which suggest that file argument should be the last.

At least on FreeBSD, this leads to incorrect cron module bahavior which
writes to root's crontab instead of users's

[gregdek]

Thanks @AMDmi3. To the current maintainers, @dsummersl, @EvanK please review according to guidelines (http://docs.ansible.com/ansible/developing_modules.html#module-checklist) and comment with text 'shipit', 'needs_revision' or 'close_me' as appropriate.

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[EvanK]

shipit

[gregdek]

Thanks again to @AMDmi3 for this PR, and thanks @dsummersl, @EvanK for reviewing. Marking for inclusion.

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[gtrafimenkov]

This change reverts 7a0b488

I guess check of platform.system() is required.

[AMDmi3]

See #2807 (summary: 7a0b488 was probably bogus, crontab always works with -u <user> <file>, including busybox).