common/io: Rewrite socket handling code to read all available data

common/io: Rewrite socket handling code to read all available data

This improves the processing of packets considerably.  It has been
observed that there can be as many as 10 packets in the socket buffer and
the current code of reading a single packet from a socket at a time is
not very optimal.  This change reads all the bytes from socket buffer and
then parses to extract multiple packets.  If there are multiple packets,
set up a timed event to process next packet.

Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Cherry-pick-from: d788bc8f7212b7dc1587ae592242dc8c876f4053

Conflicts:
	common/ctdb_io.c