It is not possible to edit the robots file in Blogger unless you host your blog on your server. Remove sitemap URL from the robots file.
I was getting same problem in google webmaster tool and try many time to change that. But now i finally got it we can not change that till it is not own blog. so better to use the feature in google webmaster tool, "fetch as google". it help you indexing all pages of your website.
Hey Mate, Disallow:/search is ok but where is Allow:/ without this derivative Google not Crawl or index your blogs because Allow:/ is here which gives Googlebot a clear idea to crawl your whole website and all posts, archives and everything except Search which we already directed Disallow, so add Allow:/ in your Robots.txt file and see the difference and in the next crawl your blog articles will start indexing in the google.....
You cannot upload the robots.txt file, but you can use the robots meta tag to control the crawling of bots on particular files.