NetworkManager fails to set ipv4.gateway for a bonding interface.

Issue

• NetworkManager fails to set ipv4.gateway for a bonding interface.

Issue sample:

[root@host1 /]# rpm -q NetworkManager
NetworkManager-1.20.0-3.el8.x86_64
[root@host1 /]# nmcli connection show bond0 | egrep "ipv4.addresses:|ipv4.gateway:|bond.options:"
ipv4.addresses:                         172.16.1.140/24
ipv4.gateway:                           172.16.1.1
bond.options:                           miimon=1000,mode=active-backup
[root@host1 /]# ip route
default via 172.16.1.1 dev bond0 proto static metric 300
172.16.1.0/24 dev bond0 proto kernel scope link src 172.16.1.140 metric 300
[root@host1 /]# nmcli con down bond0; nmcli con up bond0
Connection 'bond0' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/17)
Connection successfully activated (master waiting for slaves) (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/19)
[root@host1 /]# ip route
172.16.1.0/24 dev bond0 proto kernel scope link src 172.16.1.140 metric 300
[root@host1 /]#

Another "nmcli con up bond0" can set the ipv4.gateway.