VoldExploitTest: Don't timeout on slow netlink receivers

Impose a maximum timeout of approximately 10 seconds for
confirmNetlinkMsgReceived(). This timeout is needed to
deal with processes which may be slow to process incoming
netlink messages.

See http://code.google.com/p/android/issues/detail?id=25099
for details.

Change-Id: I8252436e4db570f169e04ee1b8c471a558639e98