zebra: Do not allow instance redistribution to happen no matter what

zebra: Do not allow instance redistribution to happen no matter what

If you have this setup:

router ospf 3
  redistribute sharp
!

and then install:
sharp install route 4.5.6.7 nexthop 192.168.100.1 1
sharp install route 4.5.6.8 nexthop 192.168.100.1 1 instance 3
sharp install route 4.5.6.9 nexthop 192.168.100.1 1 instance 4

The .8 and .9 routes are auto redistributed into ospf instance 3:

eva# show ip ospf data

OSPF Instance: 3

       OSPF Router with ID (192.168.122.1)

                AS External Link States

Link ID         ADV Router      Age  Seq#       CkSum  Route
4.5.6.7        192.168.122.1     13 0x80000001 0x477c E2 4.5.6.7/32 [0x0]
4.5.6.8        192.168.122.1      5 0x80000001 0x3d85 E2 4.5.6.8/32 [0x0]
4.5.6.9        192.168.122.1      5 0x80000001 0x338e E2 4.5.6.9/32 [0x0]

This cannot be correct behavior.  When redistributing in the absense
of an instance number the default instance of 0 should be used and should
be the only route redistributed.  Here is the correct behavior:

eva# show ip route
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route, q - queued, r - rejected, b - backup
       t - trapped, o - offload failure

K>* 0.0.0.0/0 [0/100] via 192.168.119.1, enp39s0, 00:00:28
D>* 4.5.6.7/32 [150/0] via 192.168.100.1, virbr1, weight 1, 00:00:02
D[3]>* 4.5.6.8/32 [150/0] via 192.168.100.1, virbr1, weight 1, 00:00:02
D[4]>* 4.5.6.9/32 [150/0] via 192.168.100.1, virbr1, weight 1, 00:00:02
C>* 192.168.100.0/24 is directly connected, virbr1, 00:00:28
C>* 192.168.110.0/24 is directly connected, virbr2, 00:00:28
C>* 192.168.119.0/24 is directly connected, enp39s0, 00:00:28
C>* 192.168.122.0/24 is directly connected, virbr0, 00:00:28
eva# show ip ospf data

OSPF Instance: 3

       OSPF Router with ID (192.168.122.1)

                AS External Link States

Link ID         ADV Router      Age  Seq#       CkSum  Route
4.5.6.7        192.168.122.1      6 0x80000001 0x477c E2 4.5.6.7/32 [0x0]

Signed-off-by: Donald Sharp <sharpd@nvidia.com>