bgpd: Fix holdtime not working properly when busy

bgpd: Fix holdtime not working properly when busy

Commit:  cc9f21da2218d95567eff1501482ce58e6600f54

Modified the bgp_fsm code to dissallow the extension
of the hold time when the system is under extremely
heavy load.  This was a attempt to remove the return
code but it was too aggressive and messed up this bit
of code.

Put the behavior back that was introduced in:
d0874d195d0127009a7d9c06920c52c95319eff9

Signed-off-by: Donald Sharp <sharpd@nvidia.com>
(cherry picked from commit 9a26a56c5188fd1c95e244932bc17f97b9051935)