Introduce log_ks_post_nochroot snippet

This snippet is responsible for logging the "%post --nochroot"
kickstart section actions.

Signed-off-by: Nathan Ozelim <natoze@linux.vnet.ibm.com>
Merge pull request #714 from alanoe/alanoe/introduce_log_post_nochroot_snippet

Introduce log_ks_post_nochroot snippet