isSocket() shouldn't clear socket error codes

See https://linux.die.net/man/7/socket:

SO_DOMAIN (since Linux 2.6.32)
  Retrieves the socket domain as an integer, returning a value
  such as AF_INET6. See socket(2) for details. This socket option
  is read-only.

SO_ERROR
  Get and clear the pending socket error. This socket option
  is read-only. Expects an integer.

We can rely on Linux kernel version being >=4.9 with Android S

Test: atest, TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I97cdb3fd62c7bf30205bf8cc035461da98762538
1 file changed