Silence the warnings

(cherry picked from commit open-mpi/ompi@6549c87)

Author: Ralph Castain

ompi/mca/osc/pt2pt/osc_pt2pt_data_move.c

@@ -1709,7 +1709,7 @@ int ompi_osc_pt2pt_frag_start_receive (ompi_osc_pt2pt_module_t *module)
         return OMPI_ERR_OUT_OF_RESOURCE;
     }
 
-    for (int i = 0 ; i < module->recv_frag_count ; ++i) {
+    for (unsigned int i = 0 ; i < module->recv_frag_count ; ++i) {
         OBJ_CONSTRUCT(module->recv_frags + i, ompi_osc_pt2pt_receive_t);
         module->recv_frags[i].module = module;
         module->recv_frags[i].buffer = malloc (mca_osc_pt2pt_component.buffer_size + sizeof (ompi_osc_pt2pt_frag_header_t));

ompi/mca/osc/pt2pt/osc_pt2pt_module.c

@@ -94,7 +94,7 @@ int ompi_osc_pt2pt_free(ompi_win_t *win)
     OBJ_DESTRUCT(&module->peer_lock);
 
     if (NULL != module->recv_frags) {
-        for (int i = 0 ; i < module->recv_frag_count ; ++i) {
+        for (unsigned int i = 0 ; i < module->recv_frag_count ; ++i) {
             OBJ_DESTRUCT(module->recv_frags + i);
         }