RPC validateaddress: test pwalletMain for NULL (no-wallet mode)
RPC validateaddress: test pwalletMain for NULL (no-wallet mode)

Conflicts:
	src/rpcwallet.cpp

Rebased-from: b878f6a92436e3facd700e2e10c04f541cd6421b

MidasPaymentLTD/midascoin,MidasPaymentLTD/midascoin,MidasPaymentLTD/midascoin,MidasPaymentLTD/midascoin,MidasPaymentLTD/midascoin