Add remove_ntp_dhcp option

  * Those option are WA for
    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=600661
    WA needed for extremly rare situatuon, when network dhcp provide wrong
    ntp.
  * Those option make sence to use only with dropping 'ntp-servers' request
    from dhclient.conf - unless, you totally remove dhcp client from system
  * Misc: update  run_tests.sh to latest

Change-Id: I8818eed3541f1d7bfc073cc05d8df48d124b812e
diff --git a/README.rst b/README.rst
index 800e869..e5a96e8 100644
--- a/README.rst
+++ b/README.rst
@@ -86,6 +86,15 @@
             server: ntp.nic.cz
             key_id: 2
 
+Cleanup ntp configurations left by DHCP:
+
+.. code-block:: yaml
+
+    ntp:
+      client:
+        enabled: true
+        remove_dhcp_conf: true # default false
+
 Peering (simple):
 
 .. code-block:: yaml