[librsvg] Remove unused imports

[Federico Mena Quintero <federico src gnome org>]

commit 1d2a4fc8e924d960ad51c95b2a2b1590f60e805a
Author: Federico Mena Quintero <federico gnome org>
Date:   Thu Mar 16 08:05:41 2017 -0600

    Remove unused imports

 rust/src/viewbox.rs |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/rust/src/viewbox.rs b/rust/src/viewbox.rs
index 52a816e..df36f19 100644
--- a/rust/src/viewbox.rs
+++ b/rust/src/viewbox.rs
@@ -1,6 +1,5 @@
 extern crate cairo;
 
-use std::fmt;
 use std::str::FromStr;
 
 use error::*;
@@ -63,7 +62,6 @@ impl FromStr for RsvgViewBox {
 mod tests {
     use super::*;
     use std::str::FromStr;
-    use error::*;
 
     #[test]
     fn parses_valid_viewboxes () {