add_host should not be a changed action

The action doesn't actually change anything on a system, so setting
the status to changed is wrong. add_host is much like set_fact in that
regard.

Since changed is False by default, there is no need to explicity set
it, so just create an empty dict for result and add to it from there.
Merge pull request #3343 from j2sol/add_host_changed

add_host should not be a changed action
ec2 inventory plugin: fix whitespace around connection validity test
Merge pull request #3349 from tgerla/fixec2

ec2 inventory plugin: fix whitespace around connection validity test
validate files: fix usage error in example command

visudo requires the -f option to check any other file than the default.
I've added this to the example ansible tasks.
Fixup previous apt_key patch to enable file based modes to work.
Merge pull request #3350 from billwanjohi/devel

validate files: fix usage error in example tasks
Remove a trailing quote
Merge pull request #3353 from j2sol/typo

Remove a trailing quote
Merge remote-tracking branch 'upstream/devel' into devel