remove hard coding of path for id command

git-svn-id: file:///home/svn/framework3/trunk@12902 4d416f70-5f16-0410-b530-b9f4589650da

lib/msf/core/post/linux/priv.rb

@@ -9,9 +9,13 @@ module Priv
 		# Returns true if running as root, false if not.
 		def is_root?
 			root_priv = false
-			user_id = cmd_exec("/bin/id -u")
+			user_id = cmd_exec("id -u")
 			if user_id.to_i == 0
 				root_priv = true
+			elsif user_id =~ /^\d*$/
+				root_priv = false
+			else
+				raise "Could not determine UID: #{user_id}"
 			end
 			return root_priv
 		end