Add missing return so this builds on mingw.

svn:r8649

src/common/util.c

@@ -1545,6 +1545,7 @@ path_is_relative(const char *filename)
     return 0;
   else if (filename && strlen(filename)>3 && TOR_ISALPHA(filename[0]) &&
            filename[1] == ':' && filename[2] == '\\')
+    return 0;
 #endif
   else
     return 1;