pml/ob1: add missing OBJ_DESTRUCT

An OBJ_DESTRUCT was missing for mca_pml_ob1.send_ranges causing a
memory leak. Identified by valgrind.

cmr=v1.8.2:reviewer=jsquyres

This commit was SVN r31768.

ompi/mca/pml/ob1/pml_ob1_component.c

@@ -304,6 +304,7 @@ int mca_pml_ob1_component_fini(void)
     OBJ_DESTRUCT(&mca_pml_ob1.recv_frags);
     OBJ_DESTRUCT(&mca_pml_ob1.rdma_frags);
     OBJ_DESTRUCT(&mca_pml_ob1.lock);
+    OBJ_DESTRUCT(&mca_pml_ob1.send_ranges);
 
     if( NULL != mca_pml_ob1.allocator ) {
         (void)mca_pml_ob1.allocator->alc_finalize(mca_pml_ob1.allocator);