Fix incorrect truncation of floating-point data

If the entire parenthesized division expression is cast to float, as it
was prior to this commit, C performs truncating integer division before
converting to float, which always leads to a result of zero.  `git-blame'
traces the bug to commit d5ed7e7, which
added the faulty parentheses as a matter of style. No parentheses are
necessary, since increments have higher precedence than type-casts,
type-casts have higher precedence than division, and division has
higher precedence than comparison. The operations will execute in the
desired order.

libtvm/tvm_htab.c

@@ -113,7 +113,7 @@ int htab_add(tvm_htab_t *htab, const char *k, int v)
 
 	/* Increase bucket count and rehash if the
 	   load factor is too high */
-	if((float)(++htab->num_nodes / htab->size) > HTAB_LOAD_FACTOR)
+	if((float)++htab->num_nodes / htab->size > HTAB_LOAD_FACTOR)
 		htab_rehash(htab, htab->num_nodes * 2);
 
 	return 0;