existing flows are moved to Hold state during ecmp update

[Senthilnathan Murugappan]

Started the ping from left to right.
Changed the no of service vms from 2 to 1 and observed that the continuous ping was moved to Hold state. however didnt have a problem with the flows started after the update.

vrf3 is right-vn

root@a2s42:/opt/contrail/utils# flow -l | grep -A2 9496
   131828 138.250.112.3:9496 1 (3)
                         128.57.48.3:0
(Gen: 3, K(nh):65, Action:H, Flags:, S(nh):0, Stats:122/11956, SPort 0)
--
   141060<=>450644 138.250.112.3:9496 1 (3->7)
                         128.57.48.3:0
(Gen: 1, K(nh):55, Action:F, Flags:, S(nh):104, Stats:258/25284, SPort 57685)
--
   368400<=>374048 138.250.112.3:9496 1 (2->6)
                         128.57.48.3:0
(Gen: 2, K(nh):23, Action:F, Flags:, S(nh):23, Stats:215/21070, SPort 59366)
--
   374048<=>368400 128.57.48.3:9496 1 (2->6)
                         138.250.112.3:0
(Gen: 1, K(nh):37, Action:F, Flags:, S(nh):37, Stats:0/0, SPort 62836)
--
   450644<=>141060 128.57.48.3:9496 1 (2->8)
                         138.250.112.3:0
(Gen: 1, K(nh):77, Action:F, Flags:, E:0, S(nh):77, Stats:258/25284, SPort 62836)