Update various modules for check_mode

This updates the following modules to support check_mode:
* apt_key
* apt_repository
* easy_install
* pip - will always report changed due to the way it handles state
* seboolean
* selinux
* slurp - since nothing changes, it just adds that it supports
  check_mode
* subversion - reports changed when checking out new repo and
  when updating.
* supervisorctl
* svr4pkg

See issue #2114.
Adding support for OpenWrt
Doc that fetch returns ok when src not present.
virt module doc fix
Merge pull request #2222 from sfromm/issue2114

Update various modules for check_mode
Merge pull request #2226 from skinp/openwrt_support

Adding support for OpenWrt
Merge pull request #2244 from fdavis/virt_doc_fix

virt module doc fix
Merge pull request #2240 from dorfsmay/pullreq-fetch-doc

Doc that fetch returns ok when src not present.