Revision 1505006

Merge revisions r1433848,1438408,1445080 from branches/fsfs-format7.
These introduce svn_io_file_create_empty and svn_io_file_create_binary
as alternatives to svn_io_file_create.

A few conflicts had to be resolved.

-- Copied from the merges
* subversion/include/svn_io.h
  (svn_io_file_create_empty,
   svn_io_file_create_binary): New functions. Variants of svn_io_file_create.

* subversion/libsvn_subr/io.c
  (svn_io_file_create_binary): implement most generic function.
  (svn_io_file_create,
   svn_io_file_create_empty): call the above.

* subversion/libsvn_client/patch.c
  (install_patched_prop_targets): update caller

* subversion/libsvn_fs_fs/fs.c
  (fs_open_for_recovery): ditto

* subversion/libsvn_fs_fs/fs_fs.c
  (write_config,
   create_file_ignore_eexist,
   upgrade_body,
   write_revision_zero,
   svn_fs_fs__create): same here

* subversion/libsvn_fs_fs/hotcopy.c
  (hotcopy_create_empty_dest): here

* subversion/libsvn_fs_fs/transaction.c
  (get_lock_on_filesystem,
   svn_fs_fs__create_txn): here

* subversion/libsvn_repos/repos.c
  (create_db_logs_lock,
   create_db_lock,
   create_conf): and here

* subversion/libsvn_wc/adm_files.c
  (init_adm): and finally here.