Simplify am_i_root()

[rasa]

bash-libraries/lib/libos.bash

Lines 75 to 81 in 637c5a5

	am_i_root() {
	if [[ "$(id -u)" = "0" ]]; then
	true
	else
	false
	fi
	}

can be simplified to:

am_i_root() { 
  [[ "$(id -u)" = "0" ]]
 } 

or even better:

am_i_root() { 
  (($(id -u) == 0))
}

or ever better:

am_i_root() { 
  ((${EUID:-${UID:-$(id -u)}} == 0))
}