NHRP : T4399: fix restart nhrp when adding or delete a tunnel

[fett0]

Change Summary

when you add or delete a nhrp tunnel , it restarts the opennhrp process of all tunnels which trigger any connection to be lost , this code solved it.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://phabricator.vyos.net/T4399

Component(s) name

nhrp

Proposed changes

How to test

vyos@hub-dmvpn# set protocols nhrp tunnel tun104 holding-time '400'
[edit]
vyos@hub-dmvpn# compare
[edit protocols nhrp]
+tunnel tun104 {
+    cisco-authentication pass123
+    holding-time 400
+}
[edit]
vyos@hub-dmvpn# commit

# it should reload the opennhrp services 

**Apr 27 20:01:34 hub-dmvpn systemd[1]: Reloading OpenNHRP.
Apr 27 20:01:34 hub-dmvpn opennhrp[25022]: Removing dynamic 100.64.10.2/32 nbma 100.0.0.3 dev tun100 up expires_in 0:04
Apr 27 20:01:34 hub-dmvpn opennhrp[25022]: NL-ARP(tun100) 100.64.10.2 not-reachable
Apr 27 20:01:34 hub-dmvpn systemd[1]: Reloaded OpenNHRP.******
Apr 27 20:01:34 hub-dmvpn sudo[25996]: pam_unix(sudo:session): session closed for user root
Apr 27 20:01:34 hub-dmvpn vyos-configd[24217]: Sending response 1
Apr 27 20:01:34 hub-dmvpn sudo[26016]:     root : PWD=/ ; USER=root ; COMMAND=/usr/sbin/ip route del 100.0.0.3 src 100.0.0.1 proto 42
Apr 27 20:01:34 hub-dmvpn sudo[26016]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=0)
Apr 27 20:01:34 hub-dmvpn sudo[26016]: pam_unix(sudo:session): session closed for user root
Apr 27 20:01:34 hub-dmvpn systemd[1]: opt-vyatta-config-tmp-new_config_25157.mount: Succeeded.

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly