Zero out this memory when debugging so that memory-checking debuggers

don't give read-from-unit warnings (they may not have visibility into
the ioctl writing into the memory).

This commit was SVN r5169.

src/util/if.c

@@ -248,6 +248,7 @@ static int ompi_ifinit(void)
         memcpy(&intf.if_mask, &ifr->ifr_addr, sizeof(intf.if_mask));
 
         intf_ptr = (ompi_if_t*) malloc(sizeof(ompi_if_t));
+        OMPI_DEBUG_ZERO(*intf_ptr);
         if(intf_ptr == 0) {
             ompi_output(0, "ompi_ifinit: unable to allocated %d bytes\n", sizeof(ompi_if_t));
             return OMPI_ERR_OUT_OF_RESOURCE;