Changed passing by value to passing by reference in Uid::is_root().

Author: Kixunil

src/unistd.rs

@@ -36,7 +36,7 @@ impl Uid {
         geteuid()
     }
 
-    pub fn is_root(self) -> bool {
+    pub fn is_root(&self) -> bool {
         self.0 == 0
     }
 }