Fix memory leak due to smart pointer misuse.

bug 11965932

Change-Id: I982b974b3554b0f4dc7a558107703ff605f580e6
diff --git a/cpp/rsCppStructs.h b/cpp/rsCppStructs.h
index 6834544..e45e2fb 100644
--- a/cpp/rsCppStructs.h
+++ b/cpp/rsCppStructs.h
@@ -260,7 +260,7 @@
 
 protected:
     void *mID;
-    sp<RS> mRS;
+    RS* mRS;
     std::string mName;
 
     BaseObj(void *id, sp<RS> rs);
@@ -1031,7 +1031,7 @@
      */
     class Builder {
     private:
-        sp<RS> mRS;
+        RS* mRS;
         std::vector<sp<Element> > mElements;
         std::vector<std::string> mElementNames;
         std::vector<uint32_t> mArraySizes;
@@ -1285,7 +1285,7 @@
 
     class Builder {
     protected:
-        sp<RS> mRS;
+        RS* mRS;
         uint32_t mDimX;
         uint32_t mDimY;
         uint32_t mDimZ;