Initialize 'pathname' pointer with NULL to avoid crash.

bochs/CHANGES

@@ -29,6 +29,8 @@ Changes after 2.6.8 release:
     - Added standard bus mouse support in addition to the existing InPort
       emulation code. (patch by Ben Lunt).
   - Hard drive
+    - Implemented lock mechanism for hard disk images. An image that is opened
+      in r/w mode cannot be used multiple times (e.g. by another Bochs session).
     - Several fixes in some disk image modes.
   - Serial / Parallel ports
     - Added support for changing output file at runtime.

bochs/iodev/hdimage/hdimage.cc

@@ -1445,6 +1445,7 @@ ssize_t dll_image_t::write(const void* buf, size_t count)
 redolog_t::redolog_t()
 {
   fd = -1;
+  pathname = NULL;
   catalog = NULL;
   bitmap = NULL;
   extent_index = (Bit32u)0;