Create an empty 'changes' file when a new transaction is created in FSFS.  Also enable the purge_txn routine, and add it to fs_commit so that old transactions are not left around.
Create an empty 'changes' file when a new transaction is created in
FSFS.  Also enable the purge_txn routine, and add it to fs_commit so
that old transactions are not left around.

   * subversion/libsvn_fs_fs/fs_fs.c
     (svn_fs__fs_begin_txn): Create an empty 'changes' file.
     (svn_fs__fs_purge_txn): Uncomment.
     (svn_fs__fs_commit): Remove the transaction directory after
       committing.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion