Correctly state the link state to INVALID when creating a carp interface.

Correctly state the link state to INVALID when creating a carp interface.

Since vhe are allocated with M_ZERO and INIT is also defined to be 0,
carp_set_state() would result in a no-op because of the state check.

So explicitly initialize the state of a vhe to INIT and move the state
check in carp_set_state_all() to prevent similar issues in the future.

Problem and initial diff from Johan Ymerson, thanks!

ok henning@