Avoid memory leak

According to the best practices for boost, the shared_ptr constructor
should not be called inside a function call (return in this case).

Ref: http://www.boost.org/doc/libs/1_55_0/libs/smart_ptr/shared_ptr.htm

Signed-off-by: Javier Arribas <jarribas@cttc.es>

src/algorithms/libs/gnss_sdr_valve.cc

@@ -49,7 +49,8 @@ boost::shared_ptr<gr::block> gnss_sdr_make_valve (size_t sizeof_stream_item,
         unsigned long long nitems,
         gr::msg_queue::sptr queue)
 {
-    return boost::shared_ptr<gnss_sdr_valve> (new gnss_sdr_valve (sizeof_stream_item, nitems, queue));
+    boost::shared_ptr<gnss_sdr_valve> valve_(new gnss_sdr_valve(sizeof_stream_item, nitems, queue));
+    return valve_;
 }