Fixed HDP plugin to support Heat engine

* Flag 'run_as_root' to methods 'execute_command', 'write_file_to', 'write_files_to', 'read_file_from' were added.

Change-Id: I46e55570aaeb305f002e6e18daa0adf3d757577e
Fixes: bug #1267817
Merge "Fixed HDP plugin to support Heat engine"