Version Control With Subversion Source

* subversion/svnadmin/main.c
(subcommand_createtxn): Buh-bye.
(cmd_table): Remove junk related to the 'createtxn' subcommand.

* subversion/tests/clients/cmdline/svnadmin_tests.py
(create_txn): Remove (there is no more 'createtxn').
(remove_txn): Remove (I dunno how to force the creation of a
dangling, uncommitted transaction).
(test_list): Lose references to removed tests.

* subversion/doc/book/book/ch05.xml
Try to get the svnadmin subcommands list back into sync with the app.