Fix fortify_fatal issue during DNSServiceProcessResult()

fd was checked at beginnig of DNSServiceProcessResult()
but fd was changed to -1. So, fortify_fatal was occured
when FD_SET() was called.
Abort message: 'FORTIFY: FD_SET: file descriptor -1 < 0'

Test: Build
Bug: 120910016
Bug: 121327565
Change-Id: Ib4c8dcc08223578fb53647637b44a20a4c221050
Merged-In: Ib4c8dcc08223578fb53647637b44a20a4c221050
Signed-off-by: Sehee Park <sehee32.park@samsung.com>
(cherry picked from commit 3eeb0e6b)