InnoDB has crashed during table creation.  Also, refuse to start if
files with duplicate tablespace identifiers are encountered.

fil_node_create(): Update fil_system->max_assigned_id.  This should
prevent the reuse of a space->id when InnoDB does a full crash
recovery and invokes fil_load_single_table_tablespaces().  Normally,
fil_system->max_assigned_id is initialized from
SELECT MAX(ID) FROM SYS_TABLES.

fil_open_single_table_tablespace(): Return FALSE when
fil_space_create() fails.

fil_load_single_table_tablespace(): Exit if fil_space_create() fails
and innodb_force_recovery=0.

rb://173 approved by Heikki Tuuri.  This addresses Issue #335.