tools: Fix frr-reload for ebgp-multihop TTL reconfiguration.

tools: Fix frr-reload for ebgp-multihop TTL reconfiguration.

In ebgp-multihop, there is a difference in reload behavior when TTL is
unspecified (meaning default 255) and when 255 is explicitly specified.
For example, when reloading with 'neighbor <neighbor> ebgp-multihop
255' in the config, the following difference is created. This commit
fixes that.

    Lines To Delete
    ===============
    router bgp 65001
     no neighbor 10.0.0.4 ebgp-multihop
    exit

    Lines To Add
    ============
    router bgp 65001
     neighbor 10.0.0.4 ebgp-multihop 255
    exit

The commit 767aaa3a8048 is not sufficient and frr-reload needs to be
fixed to handle both unspecified and specified cases.

Signed-off-by: Nobuhiro MIKI <nob@bobuhiro11.net>