[librsvg] Don't use "extern crate" for the xml crate

[Federico Mena Quintero <federico src gnome org>]

commit e339d724aac942b4b7ddc8bd50b7f353e11ab122
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri Mar 8 14:30:48 2019 -0600

    Don't use "extern crate" for the xml crate

 rsvg_internals/src/lib.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/rsvg_internals/src/lib.rs b/rsvg_internals/src/lib.rs
index 0d9f2a30..f88a4ada 100644
--- a/rsvg_internals/src/lib.rs
+++ b/rsvg_internals/src/lib.rs
@@ -3,7 +3,7 @@
 #![allow(clippy::too_many_arguments)]
 #![warn(unused)]
 
-extern crate xml as xml_rs;
+use ::xml as xml_rs;
 
 #[macro_use]
 extern crate bitflags;