stake/client: Fix panic on if validator doesn't exist

Closes #1505

CHANGELOG.md

@@ -101,6 +101,7 @@ BUG FIXES
 * \#1258 - printing big.rat's can no longer overflow int64
 * \#887  - limit the size of rationals that can be passed in from user input
 * \#1461 - CLI tests now no longer reset your local environment data
+* \#1505 - `gaiacli stake validator` no longer panics if validator doesn't exist
 
 ## 0.19.0
 

x/stake/client/cli/query.go

@@ -31,8 +31,9 @@ func GetCmdQueryValidator(storeName string, cdc *wire.Codec) *cobra.Command {
 			res, err := ctx.QueryStore(key, storeName)
 			if err != nil {
 				return err
+			} else if len(res) == 0 {
+				return fmt.Errorf("No validator found with address %s", args[0])
 			}
-
 			validator := types.MustUnmarshalValidator(cdc, addr, res)
 
 			switch viper.Get(cli.OutputFlag) {