openvpn: T9334: stop rendering "keepalive 0 0"

An interval of 0 is how the CLI turns keepalive off, and it rendered
"keepalive 0 0" because OpenVPN skipped its own sanity checks on that
pair. OpenVPN 2.7.6 dropped the exception and now refuses to start:
"keepalive ping: Must be an integer between 1 and 86400, not 0".

Leave the directive out of the file instead. Nothing then sets ping or
ping-restart, which is the keepalive-off the interval asked for, and a
saved configuration still commits untouched.

1 files changed, 2 insertions, 3 deletions

diff --git a/src/conf_mode/interfaces_openvpn.py b/src/conf_mode/interfaces_openvpn.py
index 2b235c057..3cf416c3c 100755
--- a/src/conf_mode/interfaces_openvpn.py
+++ b/src/conf_mode/interfaces_openvpn.py
@@ -542,9 +542,8 @@ def verify(openvpn):
         failure_count = int(keep_alive['failure_count'])
         timeout = interval * failure_count
 
-        # A zero interval renders "keepalive 0 0", on which OpenVPN skips its
-        # own sanity checks - that is how a configuration turns keepalive off,
-        # so only an enabled one has to satisfy them
+        # A zero interval turns keepalive off and renders no directive at
+        # all, so only an enabled one has to satisfy them
         if interval > 0:
             # the timeout has to be at least twice the interval, which the CLI
             # ranges do not enforce