vf_drawtext: Fix reinit to allow color changes.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/vf_drawtext.c

@@ -408,8 +408,11 @@ static int config_input(AVFilterLink *inlink)
 static int command(AVFilterContext *ctx, const char *cmd, const char *arg, char *res, int res_len, int flags)
 {
     if(!strcmp(cmd, "reinit")){
+        int ret;
         uninit(ctx);
-        return init(ctx, arg, NULL);
+        if((ret=init(ctx, arg, NULL)) < 0)
+            return ret;
+        return config_input(ctx->inputs[0]);
     }
 
     return AVERROR(ENOSYS);