Use recommended method to execute shell commands

Use default way from MCollective to execute shell commands.
We use latest version in all systems(Ubuntu and CentOS)
which most stable at now moment.
It can possible prevent problem with unexpected timeout.

Change-Id: If5a900e046ee0b0e487376df14349c56b05779e2
Related-Bug: #1320123
Merge "Use recommended method to execute shell commands"