Fix minor valgrind-found memory leaks

src/core/SkRefDict.cpp

Index: src/core/SkRefDict.cpp
===================================================================
--- src/core/SkRefDict.cpp	(revision 8291)
+++ src/core/SkRefDict.cpp	(working copy)
@@ -59,6 +59,7 @@
                 } else {
                     fImpl = rec->fNext;
                 }
+                delete rec;
             }
             return;
         }