set default maxreaders for lastseen -> 504
Adapt lastseen.lmdb's maxreaders to the serverd maxconnections setting
Corrections after latest code review
This is a 100% jimis modification
Another 100% jimis modification
Merge pull request #1610 from jeffali/up/master_rc7k_maxr_servd3

Try to solve the "maxreaders limit reached" problem