Increase block download timeout base from 10 to 20 minutes.
Increase block download timeout base from 10 to 20 minutes.

This harmonizes the block fetch timeout with the existing ping timeout
 and eliminates a guaranteed eventual failure from congestion collapse
 for a network operating right at its limit.

It's unlikely that we wouldn't suffer other failures if we were really
 anywhere near the network's limit, and a complete avoidance of congestion
 collapse risk requires (I think) an exponential back-off. So this isn't
 a major concern, but I think it's also useful for reducing the complexity
 of understanding out timeouts.

Github-Pull: #5647
Rebased-From: 3ff735c99ae75c21397079f49859b81e89a2f5f8

mockcoin/mockcoin,aspirecoin/aspire,alejandromgk/Lunar,KibiCoin/kibicoin,nmarley/dash,sipa/elements,putinclassic/putic,diggcoin/diggcoin,ColossusCoinXT/ColossusCoinXT,capitalDIGI/DIGI-v-0-10-4,zottejos/merelcoin,lakepay/lake,kleetus/bitcoinxt,rdqw/sscoin,rsdevgun16e/energi,RibbitFROG/ribbitcoin,truthcoin/blocksize-market,crowning-/dash,presstab/PIVX,ahmedbodi/test2,joulecoin/joulecoin,koharjidan/litecoin,genavarov/brcoin,ptschip/bitcoinxt,truthcoin/blocksize-market,coinkeeper/2015-06-22_18-52_viacoin,freelion93/mtucicoin,DynamicCoinOrg/DMC,RyanLucchese/energi,aburan28/elements,lakepay/lake,midnight-miner/LasVegasCoin,Darknet-Crypto/Darknet,MazaCoin/mazacoin-new,gwillen/elements,genavarov/lamacoin,biblepay/biblepay,inkvisit/sarmacoins,MazaCoin/maza,diggcoin/diggcoin,genavarov/ladacoin,genavarov/lamacoin,jtimon/elements,genavarov/brcoin,benzmuircroft/REWIRE.io,CoinProjects/AmsterdamCoin-v4,jmgilbert2/energi,koharjidan/litecoin,capitalDIGI/litecoin,tropa/axecoin,xuyangcn/opalcoin,biblepay/biblepay,cerebrus29301/crowncoin,mapineda/litecoin,Mrs-X/Darknet,freelion93/mtucicoin,pelorusjack/BlockDX,okinc/bitcoin,rsdevgun16e/energi,crowning-/dash,OstlerDev/florincoin,ivansib/sib16,GwangJin/gwangmoney-core,pstratem/elements,rdqw/sscoin,xuyangcn/opalcoin,pstratem/elements,mockcoin/mockcoin,mikehearn/bitcoinxt,pstratem/elements,inkvisit/sarmacoins,dmrtsvetkov/flowercoin,Petr-Economissa/gvidon,rdqw/sscoin,axelxod/braincoin,pinkevich/dash,OstlerDev/florincoin,lakepay/lake,aburan28/elements,biblepay/biblepay,Darknet-Crypto/Darknet,upgradeadvice/MUE-Src,dashpay/dash,Kenwhite23/litecoin,OmniLayer/omnicore,MazaCoin/mazacoin-new,presstab/PIVX,capitalDIGI/DIGI-v-0-10-4,NunoEdgarGub1/elements,PIVX-Project/PIVX,mycointest/owncoin,RibbitFROG/ribbitcoin,PandaPayProject/PandaPay,antcheck/antcoin,capitalDIGI/DIGI-v-0-10-4,aspirecoin/aspire,genavarov/brcoin,ArgonToken/ArgonToken,benzmuircroft/REWIRE.io,RyanLucchese/energi,npccoin/npccoin,48thct2jtnf/P,Mrs-X/PIVX,schinzelh/dash,ivansib/sib16,schinzelh/dash,inkvisit/sarmacoins,OmniLayer/omnicore,Thracky/monkeycoin,DMDcoin/Diamond,OstlerDev/florincoin,capitalDIGI/DIGI-v-0-10-4,OstlerDev/florincoin,slingcoin/sling-market,Bloom-Project/Bloom,rdqw/sscoin,supcoin/supcoin,pascalguru/florincoin,apoelstra/elements,OmniLayer/omnicore,thelazier/dash,Vsync-project/Vsync,Vsync-project/Vsync,lakepay/lake,LIMXTEC/DMDv3,DMDcoin/Diamond,florincoin/florincoin,Vsync-project/Vsync,PandaPayProject/PandaPay,antcheck/antcoin,ptschip/bitcoinxt,Rav3nPL/doubloons-0.10,aspirecoin/aspire,xuyangcn/opalcoin,RibbitFROG/ribbitcoin,dmrtsvetkov/flowercoin,crowning-/dash,ticclassic/ic,ingresscoin/ingresscoin,supcoin/supcoin,cerebrus29301/crowncoin,oklink-dev/bitcoin,supcoin/supcoin,okinc/bitcoin,apoelstra/elements,Rav3nPL/doubloons-0.10,CoinProjects/AmsterdamCoin-v4,genavarov/ladacoin,axelxod/braincoin,HeliumGas/helium,pelorusjack/BlockDX,apoelstra/elements,PIVX-Project/PIVX,dev1972/Satellitecoin,PIVX-Project/PIVX,capitalDIGI/DIGI-v-0-10-4,florincoin/florincoin,dev1972/Satellitecoin,nmarley/dash,OmniLayer/omnicore,CoinProjects/AmsterdamCoin-v4,CoinProjects/AmsterdamCoin-v4,fullcoins/fullcoin,koharjidan/litecoin,jmgilbert2/energi,oklink-dev/bitcoin,willwray/dash,ediston/energi,ptschip/bitcoinxt,presstab/PIVX,freelion93/mtucicoin,MonetaryUnit/MUE-Src,upgradeadvice/MUE-Src,UdjinM6/dash,sipa/elements,genavarov/lamacoin,ptschip/bitcoinxt,alejandromgk/Lunar,GwangJin/gwangmoney-core,putinclassic/putic,Mrs-X/PIVX,Kenwhite23/litecoin,Mrs-X/PIVX,slingcoin/sling-market,rsdevgun16e/energi,Thracky/monkeycoin,mockcoin/mockcoin,Electronic-Gulden-Foundation/egulden,biblepay/biblepay,slingcoin/sling-market,lakepay/lake,OstlerDev/florincoin,antcheck/antcoin,genavarov/lamacoin,ArgonToken/ArgonToken,RyanLucchese/energi,slingcoin/sling-market,nmarley/dash,capitalDIGI/litecoin,ingresscoin/ingresscoin,Petr-Economissa/gvidon,dashpay/dash,pinkevich/dash,puticcoin/putic,zottejos/merelcoin,my-first/octocoin,dev1972/Satellitecoin,mockcoin/mockcoin,UdjinM6/dash,ahmedbodi/test2,PandaPayProject/PandaPay,dmrtsvetkov/flowercoin,midnight-miner/LasVegasCoin,my-first/octocoin,pascalguru/florincoin,dmrtsvetkov/flowercoin,CoinProjects/AmsterdamCoin-v4,grumpydevelop/singularity,supcoin/supcoin,biblepay/biblepay,octocoin-project/octocoin,npccoin/npccoin,mapineda/litecoin,HeliumGas/helium,HeliumGas/helium,ivansib/sibcoin,48thct2jtnf/P,mycointest/owncoin,worldbit/worldbit,MazaCoin/maza,schinzelh/dash,ediston/energi,mikehearn/bitcoinxt,mapineda/litecoin,LIMXTEC/DMDv3,ahmedbodi/test2,xawksow/GroestlCoin,projectinterzone/ITZ,ColossusCoinXT/ColossusCoinXT,xawksow/GroestlCoin,fullcoins/fullcoin,crowning-/dash,ticclassic/ic,tropa/axecoin,kleetus/bitcoinxt,keesdewit82/LasVegasCoin,Darknet-Crypto/Darknet,Rav3nPL/doubloons-0.10,genavarov/ladacoin,MonetaryUnit/MUE-Src,fullcoins/fullcoin,dev1972/Satellitecoin,mockcoin/mockcoin,my-first/octocoin,benzmuircroft/REWIRE.io,capitalDIGI/litecoin,florincoin/florincoin,joulecoin/joulecoin,xawksow/GroestlCoin,HeliumGas/helium,Kenwhite23/litecoin,benzmuircroft/REWIRE.io,pstratem/elements,ionomy/ion,Electronic-Gulden-Foundation/egulden,kleetus/bitcoinxt,coinkeeper/2015-06-22_18-52_viacoin,tropa/axecoin,terracoin/terracoin,ivansib/sib16,florincoin/florincoin,MazaCoin/mazacoin-new,kleetus/bitcoinxt,schinzelh/dash,capitalDIGI/litecoin,DynamicCoinOrg/DMC,npccoin/npccoin,Bloom-Project/Bloom,Darknet-Crypto/Darknet,koharjidan/litecoin,mycointest/owncoin,pstratem/elements,willwray/dash,octocoin-project/octocoin,Petr-Economissa/gvidon,ivansib/sibcoin,lakepay/lake,PIVX-Project/PIVX,truthcoin/blocksize-market,grumpydevelop/singularity,gwillen/elements,Mrs-X/PIVX,Mrs-X/Darknet,octocoin-project/octocoin,pascalguru/florincoin,pstratem/elements,thelazier/dash,oklink-dev/bitcoin,mycointest/owncoin,PandaPayProject/PandaPay,ArgonToken/ArgonToken,rdqw/sscoin,jtimon/elements,thelazier/dash,CoinProjects/AmsterdamCoin-v4,MonetaryUnit/MUE-Src,coinkeeper/2015-06-22_18-52_viacoin,genavarov/brcoin,PandaPayProject/PandaPay,RyanLucchese/energi,Electronic-Gulden-Foundation/egulden,octocoin-project/octocoin,LIMXTEC/DMDv3,worldbit/worldbit,joulecoin/joulecoin,presstab/PIVX,sipa/elements,ColossusCoinXT/ColossusCoinXT,zottejos/merelcoin,tropa/axecoin,worldbit/worldbit,mapineda/litecoin,HeliumGas/helium,sipa/elements,MazaCoin/maza,ticclassic/ic,sipa/elements,mikehearn/bitcoinxt,ColossusCoinXT/ColossusCoinXT,BlockchainTechLLC/3dcoin,PIVX-Project/PIVX,Bloom-Project/Bloom,rsdevgun16e/energi,supcoin/supcoin,Petr-Economissa/gvidon,midnight-miner/LasVegasCoin,pinkevich/dash,aburan28/elements,Vsync-project/Vsync,Vsync-project/Vsync,Petr-Economissa/gvidon,dashpay/dash,pelorusjack/BlockDX,BlockchainTechLLC/3dcoin,DynamicCoinOrg/DMC,florincoin/florincoin,BlockchainTechLLC/3dcoin,aspirecoin/aspire,KibiCoin/kibicoin,ahmedbodi/test2,oklink-dev/bitcoin,koharjidan/litecoin,ediston/energi,zottejos/merelcoin,ivansib/sibcoin,mockcoin/mockcoin,Electronic-Gulden-Foundation/egulden,GwangJin/gwangmoney-core,alejandromgk/Lunar,ArgonToken/ArgonToken,RibbitFROG/ribbitcoin,projectinterzone/ITZ,MonetaryUnit/MUE-Src,fussl/elements,ivansib/sib16,ticclassic/ic,truthcoin/blocksize-market,Bloom-Project/Bloom,antcheck/antcoin,xuyangcn/opalcoin,crowning-/dash,genavarov/ladacoin,terracoin/terracoin,keesdewit82/LasVegasCoin,NunoEdgarGub1/elements,willwray/dash,xuyangcn/opalcoin,diggcoin/diggcoin,Thracky/monkeycoin,DMDcoin/Diamond,droark/elements,dev1972/Satellitecoin,putinclassic/putic,ptschip/bitcoinxt,thelazier/dash,willwray/dash,pelorusjack/BlockDX,jtimon/elements,Thracky/monkeycoin,apoelstra/elements,worldbit/worldbit,inkvisit/sarmacoins,ivansib/sib16,kleetus/bitcoinxt,Mrs-X/Darknet,ingresscoin/ingresscoin,NunoEdgarGub1/elements,MazaCoin/mazacoin-new,Mrs-X/PIVX,ingresscoin/ingresscoin,Petr-Economissa/gvidon,terracoin/terracoin,Bloom-Project/Bloom,dmrtsvetkov/flowercoin,pelorusjack/BlockDX,joulecoin/joulecoin,benzmuircroft/REWIRE.io,droark/elements,coinkeeper/2015-06-22_18-52_viacoin,UdjinM6/dash,tropa/axecoin,axelxod/braincoin,ionomy/ion,Rav3nPL/doubloons-0.10,joulecoin/joulecoin,mycointest/owncoin,ahmedbodi/test2,Mrs-X/Darknet,freelion93/mtucicoin,willwray/dash,puticcoin/putic,freelion93/mtucicoin,axelxod/braincoin,mikehearn/bitcoinxt,aburan28/elements,Electronic-Gulden-Foundation/egulden,jmgilbert2/energi,presstab/PIVX,midnight-miner/LasVegasCoin,MazaCoin/mazacoin-new,ivansib/sib16,MazaCoin/maza,okinc/bitcoin,PIVX-Project/PIVX,MazaCoin/maza,BlockchainTechLLC/3dcoin,puticcoin/putic,KibiCoin/kibicoin,ediston/energi,upgradeadvice/MUE-Src,rsdevgun16e/energi,aburan28/elements,Rav3nPL/doubloons-0.10,48thct2jtnf/P,GwangJin/gwangmoney-core,jmgilbert2/energi,pinkevich/dash,jtimon/elements,projectinterzone/ITZ,RibbitFROG/ribbitcoin,RibbitFROG/ribbitcoin,alejandromgk/Lunar,cerebrus29301/crowncoin,jmgilbert2/energi,48thct2jtnf/P,ColossusCoinXT/ColossusCoinXT,Kenwhite23/litecoin,pascalguru/florincoin,dmrtsvetkov/flowercoin,xawksow/GroestlCoin,ptschip/bitcoinxt,terracoin/terracoin,ivansib/sibcoin,ticclassic/ic,slingcoin/sling-market,Darknet-Crypto/Darknet,Thracky/monkeycoin,gwillen/elements,putinclassic/putic,pelorusjack/BlockDX,PIVX-Project/PIVX,jmgilbert2/energi,NunoEdgarGub1/elements,grumpydevelop/singularity,genavarov/ladacoin,LIMXTEC/DMDv3,ionomy/ion,fussl/elements,ivansib/sibcoin,ahmedbodi/test2,fullcoins/fullcoin,presstab/PIVX,xawksow/GroestlCoin,biblepay/biblepay,puticcoin/putic,pascalguru/florincoin,inkvisit/sarmacoins,ArgonToken/ArgonToken,PIVX-Project/PIVX,capitalDIGI/DIGI-v-0-10-4,genavarov/lamacoin,Darknet-Crypto/Darknet,fullcoins/fullcoin,NunoEdgarGub1/elements,apoelstra/elements,fullcoins/fullcoin,Bloom-Project/Bloom,keesdewit82/LasVegasCoin,nmarley/dash,gwillen/elements,Vsync-project/Vsync,midnight-miner/LasVegasCoin,DynamicCoinOrg/DMC,MazaCoin/maza,LIMXTEC/DMDv3,okinc/bitcoin,nmarley/dash,ivansib/sibcoin,upgradeadvice/MUE-Src,jtimon/elements,projectinterzone/ITZ,48thct2jtnf/P,alejandromgk/Lunar,schinzelh/dash,fussl/elements,koharjidan/litecoin,MonetaryUnit/MUE-Src,RyanLucchese/energi,freelion93/mtucicoin,DynamicCoinOrg/DMC,NunoEdgarGub1/elements,droark/elements,supcoin/supcoin,mikehearn/bitcoinxt,ingresscoin/ingresscoin,fussl/elements,mikehearn/bitcoinxt,oklink-dev/bitcoin,Kenwhite23/litecoin,puticcoin/putic,LIMXTEC/DMDv3,PandaPayProject/PandaPay,octocoin-project/octocoin,Kenwhite23/litecoin,npccoin/npccoin,capitalDIGI/litecoin,nmarley/dash,DynamicCoinOrg/DMC,ArgonToken/ArgonToken,tropa/axecoin,putinclassic/putic,zottejos/merelcoin,putinclassic/putic,grumpydevelop/singularity,coinkeeper/2015-06-22_18-52_viacoin,crowning-/dash,grumpydevelop/singularity,genavarov/lamacoin,pascalguru/florincoin,aburan28/elements,npccoin/npccoin,cerebrus29301/crowncoin,jtimon/elements,HeliumGas/helium,zottejos/merelcoin,pinkevich/dash,diggcoin/diggcoin,grumpydevelop/singularity,MonetaryUnit/MUE-Src,genavarov/brcoin,kleetus/bitcoinxt,sipa/elements,48thct2jtnf/P,antcheck/antcoin,genavarov/brcoin,terracoin/terracoin,fussl/elements,rsdevgun16e/energi,PIVX-Project/PIVX,Mrs-X/Darknet,Thracky/monkeycoin,aspirecoin/aspire,coinkeeper/2015-06-22_18-52_viacoin,octocoin-project/octocoin,oklink-dev/bitcoin,my-first/octocoin,axelxod/braincoin,xuyangcn/opalcoin,keesdewit82/LasVegasCoin,ionomy/ion,my-first/octocoin,genavarov/ladacoin,OmniLayer/omnicore,truthcoin/blocksize-market,capitalDIGI/litecoin,gwillen/elements,worldbit/worldbit,ionomy/ion,midnight-miner/LasVegasCoin,DMDcoin/Diamond,diggcoin/diggcoin,dashpay/dash,apoelstra/elements,pinkevich/dash,florincoin/florincoin,RyanLucchese/energi,okinc/bitcoin,joulecoin/joulecoin,upgradeadvice/MUE-Src,nmarley/dash,projectinterzone/ITZ,npccoin/npccoin,ediston/energi,alejandromgk/Lunar,UdjinM6/dash,gwillen/elements,fussl/elements,rdqw/sscoin,upgradeadvice/MUE-Src,terracoin/terracoin,OmniLayer/omnicore,OstlerDev/florincoin,schinzelh/dash,xawksow/GroestlCoin,willwray/dash,droark/elements,dev1972/Satellitecoin,DMDcoin/Diamond,BlockchainTechLLC/3dcoin,mycointest/owncoin,puticcoin/putic,keesdewit82/LasVegasCoin,BlockchainTechLLC/3dcoin,ingresscoin/ingresscoin,thelazier/dash,KibiCoin/kibicoin,biblepay/biblepay,biblepay/biblepay,KibiCoin/kibicoin,benzmuircroft/REWIRE.io,aspirecoin/aspire,mapineda/litecoin,truthcoin/blocksize-market,axelxod/braincoin,DMDcoin/Diamond,Mrs-X/Darknet,worldbit/worldbit,ColossusCoinXT/ColossusCoinXT,diggcoin/diggcoin,inkvisit/sarmacoins,mapineda/litecoin,ionomy/ion,cerebrus29301/crowncoin,droark/elements,dashpay/dash,my-first/octocoin,MazaCoin/mazacoin-new,Mrs-X/PIVX,Electronic-Gulden-Foundation/egulden,ticclassic/ic,slingcoin/sling-market,keesdewit82/LasVegasCoin,droark/elements,KibiCoin/kibicoin,Rav3nPL/doubloons-0.10,UdjinM6/dash,okinc/bitcoin,ediston/energi,antcheck/antcoin,cerebrus29301/crowncoin