isisd, ospfd: increase timeout to fix intermittent LDP Sync test failure

isisd, ospfd: increase timeout to fix intermittent LDP Sync test failure

Currently, IGPs are coded to receive a 'hello' message from LDP every second.
Intermittently, LDP Sync topotests are failing because the IGPs fail to
receive this 'hello' message every second.
When the LDP Sync topotests fail, LDP logs show that LDP is processing
zapi messages for 1-2 seconds.

This is a shortterm fix, in order to prevent CI pipeline failures.
The longterm fix is in progress.

Signed-off-by: Karen Schoener <karen@voltanet.io>