linux-cp: stop ignoring ENOBUFS while reading notif

linux-cp: stop ignoring ENOBUFS while reading notif

Type: improvement

Currently, while reading notifications, ENOBUFS error is ignored and
reading continues. This was done to minimize the number of notifications
that are lost due to reopening the socket.

Now that synchronization is implemented to recover from socket errors,
ignoring ENOBUFS and reading as much notifications as possible is not
actual. Before synchronization, all currently enqueued notification are
discarded in any case.

With this change, stop reading notifications if any error occurs.

Signed-off-by: Alexander Chernavin <achernavin@netgate.com>
Change-Id: I1184d9a3aa99df63ef59bc2a67be2b1e5e0e9329