ctdb-scripts: Update nfs-ganesha-callout

On debian buster, this variable doesn't exist anymore. Look at this PR
as a reference:

  https://github.com/gluster/storhaug/pull/30

Signed-off-by: Renaud Fortier <renaud.fortier@fsaa.ulaval.ca>
Reviewed-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Martin Schwenke <martins@samba.org>
Autobuild-Date(master): Thu Apr 23 08:07:51 UTC 2020 on sn-devel-184

diff --git a/ctdb/doc/examples/nfs-ganesha-callout b/ctdb/doc/examples/nfs-ganesha-callout
index f06b300c5b732c5976ca06ceed7e8d105cc7f2e8..7c7b07413ab403eedfbceb42ad0f66eda82020ff 100755 (executable)
--- a/ctdb/doc/examples/nfs-ganesha-callout
+++ b/ctdb/doc/examples/nfs-ganesha-callout
@@ -297,7 +297,7 @@ nfs_startup ()
 
        basic_start "nfs"
        _f="${procfs}/sys/net/ipv4/tcp_tw_recycle"
-       if [ "$_f" ] ; then
+       if [ -f "$_f" ] ; then
                echo 1 >"$_f"
        fi
 }