[librsvg] CHandle: restore the check for only setting the base_url before loading

[Federico Mena Quintero <federico src gnome org>]

commit c13672605613a5c34878ee12d711023f529852d2
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri Apr 12 11:44:43 2019 -0500

    CHandle: restore the check for only setting the base_url before loading

 rsvg_internals/src/c_api.rs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/rsvg_internals/src/c_api.rs b/rsvg_internals/src/c_api.rs
index 2a7711d6..f9f6a73b 100644
--- a/rsvg_internals/src/c_api.rs
+++ b/rsvg_internals/src/c_api.rs
@@ -476,9 +476,12 @@ impl ObjectImpl for CHandle {
 
 impl CHandle {
     fn set_base_url(&self, url: &str) {
-        //        if self.load_state.get() != LoadState::Start {
-        //            panic!("Please set the base file or URI before loading any data into RsvgHandle",);
-        //        }
+        let mut state = self.load_state.borrow();
+
+        match *state {
+            LoadState::Start => (),
+            _ => panic!("Please set the base file or URI before loading any data into RsvgHandle",),
+        }
 
         match Url::parse(&url) {
             Ok(u) => {