core: Switch to logging via gpgrt
* src/debug.c (errfp): Remove. (debug_init): Factor some code out to ... (safe_to_use_debug_file): new. (tid_log_callback): New. (debug_init): Rewrite to make use of gpgrt logging. (_gpgme_debug): Ditto. (_gpgme_debug_end): Remove extra LF testing code. * src/dirinfo.c (get_gpgconf_item): Remove now unneeded LFs. Realign output.