Increase the size of the system-wide dns cache

32 enteries perhaps was ok for per-process caching with ipv4 only
but adding ipv6 records makes it effectively 16 entries and making
it system wide makes is pretty useless.  Increasing to 640 entries.

bug:5841178
Change-Id: I879f8bf4d3c4d8c1708bb46d46a67c1f64b1861f
1 file changed