Add long description support to query and rquery.

Add support of long description query by %e option. Update man pages,
fix misprints and break placement in query_print function.
This commit fixes issue #468.
Do not leave temporary file on update.

Unlink temporary file immediately to guarantee that it will be removed
even if pkg update is terminated by user.
Fix race condition to avoid opening uninitialised variable repofile_unchecked
if `repo.sqlite' file is not in the archive fetched from a mirror.