Fix processor to build with clang

R=mark at http://breakpad.appspot.com/451002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1035 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/processor/linked_ptr.h

@@ -128,7 +128,7 @@ class linked_ptr {
   // Release ownership of the pointed object and returns it.
   // Sole ownership by this linked_ptr object is required.
   T* release() {
-    bool last = link_.depart();
+    link_.depart();
     T* v = value_;
     value_ = NULL;
     return v;