dbus-hash: Fix RANDOM_INDEX signed-integer-overflow on 32-bit

Found by compiling with clang -fsanitize=signed-integer-overflow etc and
running dbus-daemon on armv7.

Signed-off-by: Jami Kettunen <jami.kettunen@protonmail.com>

dbus/dbus-hash.c

@@ -127,7 +127,7 @@
  * 
  */
 #define RANDOM_INDEX(table, i) \
-    (((((intptr_t) (i))*1103515245) >> (table)->down_shift) & (table)->mask)
+    (((((uintptr_t) (i))*1103515245) >> (table)->down_shift) & (table)->mask)
 
 /**
  * Initial number of buckets in hash table (hash table statically