[librsvg] Implement Default for PaintServerUnits, to yield ObjectBoundingBox

[Federico Mena Quintero <federico src gnome org>]

commit d47b875bd6575f42addea9fa2436e8b2129d30b4
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Mar 21 14:13:11 2017 -0600

    Implement Default for PaintServerUnits, to yield ObjectBoundingBox

 rust/src/paint_server.rs |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/rust/src/paint_server.rs b/rust/src/paint_server.rs
index ecdb216..8554a87 100644
--- a/rust/src/paint_server.rs
+++ b/rust/src/paint_server.rs
@@ -23,6 +23,12 @@ impl FromStr for PaintServerUnits {
     }
 }
 
+impl Default for PaintServerUnits {
+    fn default () -> PaintServerUnits {
+        PaintServerUnits::ObjectBoundingBox
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;