Extra closing bracket in non-gcc IF_BUG_ONCE_

The 'IF_BUG_ONCE__' for non-gcc is wrong. A simple patch:

--- a/util_bug.h 2016-09-13 10:44:59
+++ b/util_bug.h 2016-09-08 20:24:45
@@ -117,7 +117,7 @@
 #else
 #define IF_BUG_ONCE__(cond,var)                                         \
   static int var = 0;                                                   \
-  if (PREDICT_UNLIKELY(cond)) ?                                         \
+  if (PREDICT_UNLIKELY(cond) ?                                          \
       (var ? 1 :                                                        \
        (var=1,                                                          \
         tor_bug_occurred_(SHORT_FILE__, __LINE__, __func__,             \

Credit to Gisle Vanem, from this tor-dev post: https://lists.torproject.org/pipermail/tor-dev/2016-September/011393.html