healthcheck_port: drop lsof in favor of awk/find
healthcheck_port: drop lsof in favor of awk/find

It seems lsof is a bit too heavy on the system when multiple
healthchecks are running in parallel.
So instead of calling a "big" process, let's split a bit things and get
to the filesystem directly in order to pick only the things we actually
need.

What changes:
- using /proc/net/{tcp,udp}, we get every socket matching the port
- using find with the right options, we can ensure at least one socket
  exists with the wanted inode(s)

The last part exits as soon as we have a match in order to make it
faster and less resource consuming.

Change-Id: I64776992a7e457781aa8ddaba359ef085d4cb77d
Partial-Bug: #1921714

openstack/tripleo-common,openstack/tripleo-common