Rename NOT_REACHED to OVS_NOT_REACHED

This allows other libraries to use util.h that has already
defined NOT_REACHED.

Signed-off-by: Harold Lim <haroldl@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>

lib/daemon.c

@@ -341,7 +341,7 @@ fork_and_wait_for_startup(int *fdp)
             } else if (retval < 0) {
                 VLOG_FATAL("waitpid failed (%s)", ovs_strerror(errno));
             } else {
-                NOT_REACHED();
+                OVS_NOT_REACHED();
             }
         }
         close(fds[0]);