tests: Change up start order of bmp tests

tests: Change up start order of bmp tests

Currently the tests appear to do this:
a) Start the neighbors
b) Start the bmp server connection
c) Look for the neighbors up
d) Look for the neighbor up messages in the bmp log

This is not great from a testing perspective in that
even though we started a) first it may not happen
until after b) happens.  Or even worse if it is
partially up ( 1 of the 2 peers ) then the dump
will have the neighbor connecting after parts
of the table.  This doesn't work too well because
the SEQ number is something that is kept and compared
to to make sure only new data is being looked at.

Let's modify the startup configuration to start
the bmp server first and then have a delayopen
on the bgp neighbor statements so that the bmp
peering can come up first.

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