Remove an extraneous parenthesis in IF_BUG_OHNCE__

Fixes bug 20141; bugfix on 0.2.9.1-alpha.

Patch from Gisle Vanem.

changes/bug20141

@@ -0,0 +1,4 @@
+  o Minor bugfixes (compilation):
+    - Fix a syntax error in the IF_BUG_ONCE__() macro in non-
+      GCC-compatible compilers. Fixes bug 20141; bugfix on
+      0.2.9.1-alpha. Patch from Gisle Vanem.

src/common/util_bug.h

@@ -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__,             \