Fix -rpcwait with -netinfo printing negative time durations
Fix -rpcwait with -netinfo printing negative time durations

Fixes negative time duration values in the "send", "recv",
and "age" columns (potentially the "txn" and "blk" columns also)
for the first run of -rpcwait -netinfo after bitcoind startup.

To reproduce, start bitcoind on mainnet and run
`bitcoin-cli -rpcwait -netinfo <n>` where n is 1 or larger.

The negative times will be larger/more apparent with a slower
CPU speed or e.g. higher checkblocks/checklevel config option
settings.

namecoin/namecoin-core,GroestlCoin/bitcoin,Xekyo/bitcoin,AkioNak/bitcoin,lateminer/bitcoin,mruddy/bitcoin,GroestlCoin/GroestlCoin,ajtowns/bitcoin,instagibbs/bitcoin,bitcoin/bitcoin,particl/particl-core,mruddy/bitcoin,bitcoin/bitcoin,jamesob/bitcoin,tecnovert/particl-core,domob1812/bitcoin,AkioNak/bitcoin,sstone/bitcoin,sipsorcery/bitcoin,fanquake/bitcoin,particl/particl-core,namecoin/namecoin-core,GroestlCoin/GroestlCoin,Xekyo/bitcoin,instagibbs/bitcoin,GroestlCoin/bitcoin,instagibbs/bitcoin,GroestlCoin/GroestlCoin,fujicoin/fujicoin,andreaskern/bitcoin,sipsorcery/bitcoin,mruddy/bitcoin,GroestlCoin/bitcoin,GroestlCoin/bitcoin,jamesob/bitcoin,ajtowns/bitcoin,jamesob/bitcoin,tecnovert/particl-core,kallewoof/bitcoin,jambolo/bitcoin,sstone/bitcoin,tecnovert/particl-core,sstone/bitcoin,bitcoin/bitcoin,jamesob/bitcoin,fanquake/bitcoin,bitcoinsSG/bitcoin,tecnovert/particl-core,bitcoin/bitcoin,fujicoin/fujicoin,particl/particl-core,Xekyo/bitcoin,jambolo/bitcoin,mruddy/bitcoin,particl/particl-core,Xekyo/bitcoin,instagibbs/bitcoin,lateminer/bitcoin,AkioNak/bitcoin,bitcoinsSG/bitcoin,GroestlCoin/bitcoin,jambolo/bitcoin,fujicoin/fujicoin,Xekyo/bitcoin,namecoin/namecore,sipsorcery/bitcoin,jambolo/bitcoin,namecoin/namecoin-core,sipsorcery/bitcoin,sstone/bitcoin,bitcoinsSG/bitcoin,jambolo/bitcoin,namecoin/namecore,andreaskern/bitcoin,Xekyo/bitcoin,tecnovert/particl-core,domob1812/bitcoin,instagibbs/bitcoin,domob1812/bitcoin,fujicoin/fujicoin,fanquake/bitcoin,kallewoof/bitcoin,mruddy/bitcoin,domob1812/bitcoin,bitcoinsSG/bitcoin,andreaskern/bitcoin,mruddy/bitcoin,lateminer/bitcoin,ajtowns/bitcoin,namecoin/namecore,jamesob/bitcoin,andreaskern/bitcoin,tecnovert/particl-core,ajtowns/bitcoin,andreaskern/bitcoin,sstone/bitcoin,sstone/bitcoin,bitcoin/bitcoin,bitcoinsSG/bitcoin,fanquake/bitcoin,domob1812/bitcoin,andreaskern/bitcoin,AkioNak/bitcoin,namecoin/namecoin-core,namecoin/namecore,namecoin/namecoin-core,sipsorcery/bitcoin,GroestlCoin/GroestlCoin,kallewoof/bitcoin,jambolo/bitcoin,namecoin/namecoin-core,kallewoof/bitcoin,lateminer/bitcoin,bitcoin/bitcoin,fanquake/bitcoin,AkioNak/bitcoin,ajtowns/bitcoin,namecoin/namecore,jamesob/bitcoin,kallewoof/bitcoin,fanquake/bitcoin,lateminer/bitcoin,GroestlCoin/bitcoin,particl/particl-core,sipsorcery/bitcoin,lateminer/bitcoin,fujicoin/fujicoin,GroestlCoin/GroestlCoin,AkioNak/bitcoin,bitcoinsSG/bitcoin,instagibbs/bitcoin,GroestlCoin/GroestlCoin,fujicoin/fujicoin,kallewoof/bitcoin,particl/particl-core,ajtowns/bitcoin,namecoin/namecore,domob1812/bitcoin