(main): Fix checking of ef_open()'s value. Fixes program exit status

(main): Fix checking of ef_open()'s value.  Fixes program exit status
when files can't be opened.

(logerror): The version from libcommon.a does the right thing since
log.c rev. 1.17.  Use it, remove local version.

(log_last_commands): No longer referenced by library code, remove.