MFC: Fix post-start check when unbound.conf has moved.
On behalf of: des
Reported by: phk@
Sponsored by: Rubicon Communications, LLC ("Netgate")
Approved by: re (cperciva)
(cherry picked from commit 409388cfac49a312034e9397c870e3f81ff90734)
(cherry picked from commit c6aa83342e5deccc51f627fcb92ca083fe798a3b)