node_health_check: Various updates
node_health_check: Various updates

- Removed text from Report's "PURPOSE" section, which was referring to the "MANUAL CHECK LIST" (not needed anymore).
- Removed curl command (no longer using the api_address), instead using scylla --version
- Added -v flag in iptables command, for more verbosity
- Added support to for OEL (Oracle Enterprise Linux) - minor fix
- Some text changes - minor
- OEL support indentation fix + collecting all files under /etc/scylla
- Added line seperation under cp output message

Signed-off-by: Tomer Sandler <d6911363a106df680044b70c03ec73e09e9e98e6@scylladb.com>
Message-Id: <20170828131429.4212-1-d6911363a106df680044b70c03ec73e09e9e98e6@scylladb.com>

scylladb/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,duarten/scylla,avikivity/scylla,avikivity/scylla