Add conversion from legacy keystore if it exists.
Add conversion from legacy keystore if it exists.

jrick/btcwallet,decred/dcrwallet,btcsuite/btcwallet,synrg-labs/btcwallet,jrick/btcwallet,Roasbeef/btcwallet,Stash-Crypto/btcwallet,btcsuite/btcwallet,jrick/dcrwallet,synrg-labs/btcwallet,jrick/dcrwallet,Stash-Crypto/btcwallet,decred/dcrwallet,Roasbeef/btcwallet