[leasefile] base support function cleanup
[dhcp4] get lease applied
[leasefile.c] cleanup leasefile a bit

more to come
[leasefile] function prototypes

s/parent/node in functions
[leasefile] kill unneeded functions
[leasefile] commit to using xml doc in lease file write
[leasefile] cleanup

remove bogus ni_error()'s
return NULL if unable to get/dump dhcp/dhcp6 data
check for null root node before reading document
kill calls to deleted __test functions
[leasefile] remove all KM debus