Avoid needless overhead of wrapping owner's deleter in deleter_wrapper if

shared_from_this has not been called yet, as Peter suggested
earlier.



[SVN r44448]

libs/smart_ptr

@@ -1 +1 @@
-Subproject commit 16828c9c0ab9b5d471f27704b5e69c9e718f1d40
+Subproject commit 9365853fde3061acbdd11b74b0218b80d9ef4ce0