When editing the OAM Floating IP in Horizon, the warning message does
not mention that the user needs to lock/unlock the controllers for the
changes to be applied. The warning messages now reflects that.
Closes-Bug: 1795960
Change-Id: I9117f768a9d423b538ce01db5659b2015880ef3b
Signed-off-by: Kristine Bujold <kristine.bujold@windriver.com>