Every other Ironic python agent kernel parameter is prefixed with "ipa-".
This patch allows users to use the old "lldp-timeout" parameter or the new
"ipa-lldp-timeout" parameter. Warning message is logged if "lldp-timeout"
parameter is used.
(Also fixed typo while I'm at it.)
Change-Id: Icc05ead31506628e4926be6549916a19cad48db3
Closes-Bug: #1588325