vere: clean up terminal on invalid fake ship name
vere: clean up terminal on invalid fake ship name

Currently when creating a fake ship, if an invalid ship name is given,
then the program exits without ever cleaning up the terminal. This
results in  a bugged termianal that requires closing and repopening
or using the `reset` cmd.

This commits adds a call to `u3_term_log_exit()` and `fflush(stdout)`
before calling `exit(1)` to ensure proper cleanup.

Address issue #5914

urbit/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,urbit/urbit