Fix: Remove first space char

Before we assumed 5 chars for printing the size of a node. This change
allows us to check if we need 5 chars or if we can manage with 4 which
may save us a character.

(1023B = 5 chars, 1.2K = 4 chars)

Note: Mac test runners create very long filenames in tmp directories. To
fix this we must either
1) Tell the terminal it has a very wide width
2) Duplicate the code to reduce the size of the filename (add .. at the
   end).

This commit changes from (2) to (1)

tests/test_flags.rs

@@ -73,8 +73,8 @@ pub fn test_ignore_dir() {
 #[test]
 pub fn test_with_bad_param() {
     let mut cmd = Command::cargo_bin("dust").unwrap();
-    let stderr = cmd.arg("-").unwrap().stderr;
-    let stderr = str::from_utf8(&stderr).unwrap();
+    let result = cmd.arg("bad_place").unwrap();
+    let stderr = str::from_utf8(&result.stderr).unwrap();
     assert!(stderr.contains("Did not have permissions for all directories"));
 }