net: stop both net/net_processing before destroying them
net: stop both net/net_processing before destroying them

This should avoid either attempting to use an invalid reference/pointer to the
other.

Github-Pull: #10756
Rebased-From: 2525b972af6645ca239ac1078cffb132b402bfbb

digibyte/digibyte,wangxinxi/litecoin,qtumproject/qtum,digibyte/digibyte,Jcing95/iop-hd,tecnovert/particl-core,GroestlCoin/GroestlCoin,tecnovert/particl-core,GroestlCoin/bitcoin,wangxinxi/litecoin,romanornr/viacoin,Anfauglith/iop-hd,GroestlCoin/GroestlCoin,GroestlCoin/GroestlCoin,BitzenyCoreDevelopers/bitzeny,tecnovert/particl-core,digibyte/digibyte,GroestlCoin/GroestlCoin,GroestlCoin/bitcoin,Anfauglith/iop-hd,particl/particl-core,Jcing95/iop-hd,digibyte/digibyte,BitzenyCoreDevelopers/bitzeny,romanornr/viacoin,GroestlCoin/bitcoin,wangxinxi/litecoin,qtumproject/qtum,Jcing95/iop-hd,gjhiggins/vcoincore,gjhiggins/vcoincore,Anfauglith/iop-hd,Anfauglith/iop-hd,GroestlCoin/bitcoin,gjhiggins/vcoincore,UFOCoins/ufo,wangxinxi/litecoin,UFOCoins/ufo,GroestlCoin/bitcoin,Jcing95/iop-hd,gjhiggins/vcoincore,particl/particl-core,UFOCoins/ufo,particl/particl-core,wangxinxi/litecoin,wangxinxi/litecoin,qtumproject/qtum,qtumproject/qtum,digibyte/digibyte,qtumproject/qtum,BitzenyCoreDevelopers/bitzeny,romanornr/viacoin,tecnovert/particl-core,qtumproject/qtum,UFOCoins/ufo,particl/particl-core,GroestlCoin/bitcoin,Jcing95/iop-hd,GroestlCoin/GroestlCoin,particl/particl-core,tecnovert/particl-core,romanornr/viacoin,gjhiggins/vcoincore,digibyte/digibyte,UFOCoins/ufo,romanornr/viacoin,BitzenyCoreDevelopers/bitzeny,gjhiggins/vcoincore,romanornr/viacoin,Anfauglith/iop-hd,UFOCoins/ufo,BitzenyCoreDevelopers/bitzeny,GroestlCoin/GroestlCoin,BitzenyCoreDevelopers/bitzeny,Anfauglith/iop-hd,qtumproject/qtum,Jcing95/iop-hd,particl/particl-core,tecnovert/particl-core