crate download: don't print that a crate was the largest download if it was the only download

before:

    Updating crates.io index
  Downloaded procs v0.8.4
  Downloaded 1 crates (1.1 MB) in 2.90s (largest was `procs` at 1.1 MB)
  Installing procs v0.8.4

after:

    Updating crates.io index
  Downloaded procs v0.8.4
  Downloaded 1 crates (1.1 MB) in 1.50s
  Installing procs v0.8.4

Author: matthiaskrgr

src/cargo/core/package.rs

@@ -951,7 +951,10 @@ impl<'a, 'cfg> Drop for Downloads<'a, 'cfg> {
             ByteSize(self.downloaded_bytes),
             util::elapsed(self.start.elapsed())
         );
-        if self.largest.0 > ByteSize::mb(1).0 {
+        // print the size of largest crate if it was >1mb
+        // however don't print if only a single crate was downloaded
+        // because it is obvious that it will be the largest then
+        if self.largest.0 > ByteSize::mb(1).0 && self.downloads_finished > 1 {
             status.push_str(&format!(
                 " (largest was `{}` at {})",
                 self.largest.1,