Fix servenv of incorrect variable for moveFlags

- It looks like cmd.Use was accidenatlly used instead of `cmd.Name()`
- `cmd.Use` is actaully the help text, not the name of the command
- This was not allowing commands to make use of registered/available flags for their use (IE --grpc_...)

Extra:
- Since a lot of these flags are initialized by functional callback, we should not rely on go-lang `init()` as the order can change and be somewhat arbitrary
- Refactored `init()` to `initializedFlags()` and called at runtime for vtclient

Signed-off-by: Kyle Johnson <kylej@hubspot.com>

go/cmd/vtclient/cli/vtclient.go

@@ -82,7 +82,7 @@ var (
 	seqChan = make(chan int, 10)
 )
 
-func init() {
+func InitializeFlags() {
 	servenv.MoveFlagsToCobraCommand(Main)
 
 	Main.Flags().StringVar(&server, "server", server, "vtgate server to connect to")

go/cmd/vtclient/vtclient.go

@@ -22,6 +22,7 @@ import (
 )
 
 func main() {
+	cli.InitializeFlags()
 	if err := cli.Main.Execute(); err != nil {
 		log.Exit(err)
 	}

go/vt/servenv/servenv.go

@@ -336,7 +336,7 @@ func ParseFlagsForTests(cmd string) {
 // the given cobra command, then copies over the glog flags that otherwise
 // require manual transferring.
 func MoveFlagsToCobraCommand(cmd *cobra.Command) {
-	moveFlags(cmd.Use, cmd.Flags())
+	moveFlags(cmd.Name(), cmd.Flags())
 }
 
 // MovePersistentFlagsToCobraCommand functions exactly like MoveFlagsToCobraCommand,
@@ -347,7 +347,7 @@ func MoveFlagsToCobraCommand(cmd *cobra.Command) {
 // Useful for transferring flags to a parent command whose subcommands should
 // inherit the servenv-registered flags.
 func MovePersistentFlagsToCobraCommand(cmd *cobra.Command) {
-	moveFlags(cmd.Use, cmd.PersistentFlags())
+	moveFlags(cmd.Name(), cmd.PersistentFlags())
 }
 
 func moveFlags(name string, fs *pflag.FlagSet) {