Fix a few compiler warnings issued by clang 3.6.0


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14969 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/helgrind/libhb_core.c b/helgrind/libhb_core.c
index b146e0a..d39f5a7 100644
--- a/helgrind/libhb_core.c
+++ b/helgrind/libhb_core.c
@@ -2383,7 +2383,7 @@
 static void VTS__show ( const VTS* vts )
 {
    Word      i, n;
-   tl_assert(vts && vts->ts);
+   tl_assert(vts);
 
    VG_(printf)("[");
    n =  vts->usedTS;
@@ -2402,7 +2402,7 @@
    UWord i, n;
    ThrID idx_thrid = Thr__to_ThrID(idx);
    stats__vts__indexat_slow++;
-   tl_assert(vts && vts->ts);
+   tl_assert(vts);
    n = vts->usedTS;
    for (i = 0; i < n; i++) {
       ScalarTS* st = &vts->ts[i];