Patch #6258.

Patch #6258.

* command.c (report_state_mismatch): Replace code to construct an
error message from bits and pieces by a switch statement that
hard-codes each possible error.  Makes i18n easier.
Suggested by Chusslove Illich <caslav.ilic@gmx.net>.

* file-handle-def.c (fh_lock): Add comment that TYPE should be
marked with N_() in the caller.  Added these markings to each
caller too.  Should make i18n easier.
Suggested by Chusslove Illich <caslav.ilic@gmx.net>.