patchfast-import: remove duplicated option-parsing line

>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> Another tidbit I noticed in my foray into fast-import earlier today.
>
>  builtin/fast-import.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/builtin/fast-import.c b/builtin/fast-import.c
> index 70d7d25eed..dd4d09cece 100644
> --- a/builtin/fast-import.c
> +++ b/builtin/fast-import.c
> @@ -3399,7 +3399,6 @@ static int parse_one_feature(const char *feature, int from_stream)
>  		option_rewrite_submodules(arg, &sub_marks_to);
>  	} else if (skip_prefix(feature, "rewrite-submodules-from=", &arg)) {
>  		option_rewrite_submodules(arg, &sub_marks_from);
> -	} else if (skip_prefix(feature, "rewrite-submodules-from=", &arg)) {
>  	} else if (!strcmp(feature, "get-mark")) {
>  		; /* Don't die - this feature is supported */
>  	} else if (!strcmp(feature, "cat-blob")) {

> Commit 1bdca81641 (fast-import: add options for rewriting submodules,
> 2020-02-22) accidentally added two lines parsing the option
> "rewrite-submodules-from". This didn't do anything in practice, because
> they're in an if/else chain and so the second one can never trigger.
> 
> Signed-off-by: Jeff King <peff@peff.net>