Add comment about never updating nTimeOffset past 199 samples
Add comment about never updating nTimeOffset past 199 samples

Refer to issue #4521 for details.

(cherry picked from commit 93659379bdedc29a87fe351ba2950a2c976aebd9)

reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin