Fixing some bugs in _compute_delegate() in TaskExecutor
Fixing some bugs in _compute_delegate() in TaskExecutor

* Clearing interpreter settings from variables, so those set for the
  original host aren't incorrectly applied to the delegated to host
* Fixed incorrect string for remote user in delegated hosts hostvars
* Properly looking for multiple possiblities in the delegated-to hosts
  hostvars (ansible_ssh_host vs. ansible_host)

thaim/ansible,thaim/ansible