[ovs-git] [ovn-org/ovn] dfaac3: ovn-nbctl: fix sigsegv when nexthop arg is missing

[Moshe Levi]

  Branch: refs/heads/branch-20.06
  Home:   https://github.com/ovn-org/ovn
  Commit: dfaac335de396a5b3f659bb5a7ae734464708120
      https://github.com/ovn-org/ovn/commit/dfaac335de396a5b3f659bb5a7ae734464708120
  Author: Moshe Levi <moshele at nvidia.com>
  Date:   2021-01-04 (Mon, 04 Jan 2021)

  Changed paths:
    M utilities/ovn-nbctl.c

  Log Message:
  -----------
  ovn-nbctl: fix sigsegv when nexthop arg is missing

running the following command will result core dump

$ ovn-nbctl lr-policy-add lr0 2000 ip4.src==192.168.0.15 reroute
Segmentation fault (core dumped)

This commit add the missing return when the nexthop is missing

with the fix running the same comand will result the currect output
$ ovn-nbctl lr-policy-add lr0 2000 ip4.src==192.168.0.15 reroute
ovn-nbctl: Nexthop is required when action is reroute.

Signed-off-by: Moshe Levi <moshele at nvidia.com>
Signed-off-by: Numan Siddique <numans at ovn.org>

(cherry-picked from master commit 5cdfecef6e84f47dcca83c221c1137968e424e5b)