squash! Optimize legacy intro point digest calculation.

changes/bug23107

@@ -1,6 +1,6 @@
   o Code simplification and refactoring:
     - Put a SHA1 public key digest in hs_service_intro_point_t, and use it in
       register_intro_circ() and service_intro_point_new(). This prevents the
-      digest from being re-calculated each time. Fixes bug 23107. Patch by 
+      digest from being re-calculated each time. Closes ticket 23107. Patch by
       Neel Chauhan.