that changes the state to dbfile_change_magic().  Reduce code
duplication by teaching foutput_header() to handle old file
formats.
* src/server/simple-cache.c (pre_sync): Adjusted to new API of
dbfile_open_write(), including removing calls to foutput_header().
(save_one_text): Extracted parts of the functionality to
dbfile_change_magic().
* src/server/ram-output.c (foutput_header): Moved support for file
formats 0, 1 and 2 here from sync_output_header().
* src/server/ram-io.c, src/server/ram-io.h
(dbfile_open_write): New argument: magic.  Write a file header
with the specified state.
(dbfile_change_magic): New function, extracted from
cache_sync_all() in dbck-cache.c and save_one_text().
* src/server/dbck-cache.c (sync_output_header): Removed.
The ability to emit old-style headers moved to foutput_header().
(cache_sync_all): Adjusted to new API of dbfile_open_write,
including removing calls to sync_output_header().  Use
dbfile_change_magic() instead of rewind() and
sync_output_header().
* src/server/Makefile.am (libcheck_a_SOURCES): Added
server-time.c.