walletimport: doesn't understand erc55 addresses in the dump format

[prasannavl]

Summary

• walletimport doesn't understand 0x addresses in the dump and as such the import fails.
• walletdump after generation of addresses (getnewaddress) beyond the original key pool will also generate ERC55.

To reproduce

• Create a new wallet.
• Generate a few addresses with getnewaddress
• dumpwallet
• Attempt to reimport it again with importwallet

Temporary workaround

• Using a regex replace to remove the erc55 addresses should make the dump file important again.
• Eg: sed "s/\(addr=\w\+\),0x\w\+/\1/g" wallet.dump > wallet.importable.dump to generate a new importable file.