mandb: Rearrange database path operations

Moving these into "methods" of `struct dbpaths` makes the control flow
clearer by avoiding lots of inlined `#ifdef`s.

I fixed a possible crash in `mandb -f` in the process, exposed by the
clearer control flow.

* src/mandb.c (dbpaths_init, dbpaths_copy_to_tmp, dbpaths_remove_tmp):
New functions.
(finish_up): Rename to ...
(dbpaths_rename_from_tmp): ... this.
(do_chown): Rename to ...
(dbpaths_chown_if_possible): ... this.
(cleanup_sigsafe): Rename to ...
(dbpaths_unlink_tmp): ... this, and take a `struct dbpaths *` argument
rather than `void *`.
(cleanup): Rename to ...
(dbpaths_free_elements): ... this, and take a `struct dbpaths *`
argument rather than `void *`.
(mandb, process_manpath): Use new `dbpaths_*` functions.  Only call
`dbpaths_rename_from_tmp` if `run_mandb` is set (in practice this was
always true anyway but this makes it clearer).  Only call
`dbpaths_chown_if_possible` if `run_mandb` is set and
`dbpaths_rename_from_tmp` was called (this may have caused a crash in
some edge cases involving `mandb -f`).

0 files changed, 0 insertions, 0 deletions