pull request #1177 - saving bones

Pull request from janne-hmp:  defer releasing the memory for the
current level by having savebones() using write mode rather than
write+free mode.  nh_terminate() -> freedyanmicdata() will free the
current level.

Matters for 3rd party html dumplog (which nethack doesn't support).

The commit message is misformatted and misleading but it's a bit
late to fix that now.

Closes #1177

src/bones.c

@@ -576,7 +576,7 @@ savebones(int how, time_t when, struct obj *corpse)
     }
     c = (char) (strlen(bonesid) + 1);
 
-    nhfp->mode = WRITING | FREEING;
+    nhfp->mode = WRITING;
     store_version(nhfp);
     store_savefileinfo(nhfp);
     if (nhfp->structlevel) {