Fix updateValidatorDistInfoFromPool (#3046)

Fixes regression introduced by #2984.
Continuiation of #3033 , which didn't fix the simulation issues.
(candidate) Complete solution for #3019, 9002 halt bug.

From #2984, it isn't sufficient to take the fee pool rewards of a validator. Since we don't track delegator accums (as we do with validator accums), and because onValidatorModified >updateValidatorDistInfoFromPool is also being called upon delegation updates (or at least I believe this is the reason), it is necessary to also withdraw self delegation.

TODO: I don't think self-delegation should be required to be modified here... consider using a delegation hook to do the self-delegation withdraw part instead, e.g. splitting the updateValidatorDistInfoFromPool function into two. It might not result in cleaner code, however. Think hard.

cmd/gaia/cmd/gaiakeyutil/main.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"os"
+
+	"github.com/tendermint/tendermint/libs/bech32"
+)
+
+var bech32Prefixes = []string{"cosmos", "cosmospub", "cosmosvaloper", "cosmosvaloperpub", "cosmosvalcons", "cosmosvalconspub"}
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Println("Must specify an input string")
+	}
+	arg := os.Args[1]
+	runFromBech32(arg)
+	runFromHex(arg)
+}
+
+// Print info from bech32.
+func runFromBech32(bech32str string) {
+	hrp, bz, err := bech32.DecodeAndConvert(bech32str)
+	if err != nil {
+		fmt.Println("Not a valid bech32 string")
+		return
+	}
+	fmt.Println("Bech32 parse:")
+	fmt.Printf("Human readible part: %v\nBytes (hex): %X\n",
+		hrp,
+		bz,
+	)
+}
+
+func runFromHex(hexaddr string) {
+	bz, err := hex.DecodeString(hexaddr)
+	if err != nil {
+		fmt.Println("Not a valid hex string")
+		return
+	}
+	fmt.Println("Hex parse:")
+	fmt.Println("Bech32 formats:")
+	for _, prefix := range bech32Prefixes {
+		bech32Addr, err := bech32.ConvertAndEncode(prefix, bz)
+		if err != nil {
+			panic(err)
+		}
+		fmt.Println("  - " + bech32Addr)
+	}
+}