tools: Use platform abstraction for renaming files.
* tools/gpgconf-comp.c (gc_component_change_options): Use 'gnupg_rename_file'. Also, block signals across all renames in an attempt to make the whole process atomic.
Werner asked me to make gpgconf use the platform abstractions that
were introduced after gpgconf's inception.
- Signed-off-by: Justus Winter <justus@g10code.com>