iscsi-scst: Suppress a compiler warning (merge r5614 from trunk)

git-svn-id: http://svn.code.sf.net/p/scst/svn/branches/3.0.x@5696 d57e44dd-8a1f-0410-8b47-8ef2f437770f

iscsi-scst/usr/chap.c

@@ -344,7 +344,8 @@ static int chap_rand(void)
 
     fd = open("/dev/urandom", O_RDONLY);
     assert(fd != -1);
-    (void)read(fd, &r, sizeof(r));
+    if (read(fd, &r, sizeof(r)) < sizeof(r)) {
+    }
     close(fd);
     return r;
 }