Fix typo (LIBLDNSADD -> LIBLDNS) to fix "make checkdpadd"

X-MFC with: r269648
Phabric: D634
Approved by: jmmv (mentor)
Add missing libraries to DPADD; sort DPADD so DPADD and LDADD match up

This fixes "make checkdpadd"

Approved by: jmmv (mentor)
MFC after: 2 weeks
Phabric: D630
PR: 192765