bgpd: stop sending nexthop set by "route-map in" to eBGP peers

bgpd: stop sending nexthop set by "route-map in" to eBGP peers

Problem reported that when a "neighbor x.x.x.x route-map FOO in"
set a next-hop value, that modified next-hop value was also sent
to eBGP peers.  This is incorrect since bgp is expected to set
next-hop to self when sending to eBGP peers unless third party
next-hop on a shared segment is true.  This fix modifies the
behavior to stop sending the modified next-hop to eBGP peers
if the route-map was applied inbound on another peer.

Ticket: CM-26025
Signed-off-by: Don Slice <dslice@cumulusnetworks.com>