network: Adds the functionality to parse uid in netlink messages.

Netlink notifications about the state of the modem contains uid too.
This patch adds the functionality to add that. It also fixes the bug to
parse the timestamp in the message even in cases where the length is
greater than expected.

Bug: 28527904
Change-Id: I4643bff3eb5b1ffa2dc0b78f1c6947d60487e0d8
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>