test_rtnetlink: Increase interations in WithSingleInterface

We were hitting test failures caused by

    EXPECT_EQ(true, isInterfaceAdded("igb5"));

at the end of the WithSingleInterface case. There appears to be a race
condition between the netlink handling and the timer expiry, so
increment the number of retries for test stability.

Change-Id: I6cd2e4e95ee4d183466c73fa8a36a5580f566227
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
1 file changed