s3:vfs_fileid: always add the 'nolock' behavior via file_id.extid

s3:vfs_fileid: always add the 'nolock' behavior via file_id.extid

file_id.extid was filled with getpid() by 'fsname_norootdir_ext'.

However instead of forcing the existing 'hostname' algorithm for the 'nolock'
case, we'll now generate file_id.extid also based the hostname, vnn
and for 'fsname_norootdir_ext' also the pid.

This simplifies further changes and gives us the ability to generate stable
results for file_id.{devid,inode} based on the main algorithm. This is important
as we have a push_file_id_16() helper function used in places to generate a
stable identifier of the file that is also client visible and might be stored on
stable storage (acl_tdb, xattr_tdb). While the file_id.extid is only used
internally in volatile databases.

Review with: git show --patience

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>