proc connector: fix info leaks

[ Upstream commit e727ca82e0e9616ab4844301e6bae60ca7327682 ]

Initialize event_data for all possible message types to prevent leaking
kernel stack contents to userland (up to 20 bytes). Also set the flags
member of the connector message to 0 to prevent leaking two more stack
bytes this way.

Cc: stable@vger.kernel.org  # v2.6.15+
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>