Fix interaction between --listed-incremental and -C

* src/incremen.c (read_directory_file): Execute eventual -C dir
after opening the snapshot file.
(collect_and_sort_names): Remove call to chdir_do
* tests/incr05.at, tests/incr06.at: Use relative file names for
snapshot files.

src/incremen.c

@@ -1324,6 +1324,13 @@ read_directory_file (void)
       return;
     }
 
+  /* Consume the first name from the name list and reset the
+     list afterwards.  This is done to change to the new
+     directory, if the first name is a chdir request (-C dir),
+     which is necessary to recreate absolute file names. */
+  name_from_list ();
+  blank_name_list ();
+  
   if (0 < getline (&buf, &bufsize, listed_incremental_stream))
     {
       char *ebuf;

src/names.c

@@ -903,7 +903,7 @@ collect_and_sort_names (void)
 			_("Only one -C option is allowed with "
 			  "--listed-incremental")));
 	}
-      chdir_do (namelist->change_dir);
+
       read_directory_file ();
     }