createrepo: Implement --dbpath command line option
--dbpath option can be used in cases where users don't want
createrepo to use system rpm db to avoid possible collisiouns
with other programs.
For bitbake builds it would be possible to specify different
databases even for every createrepo run. Considering that rootfs
builds can run multiple createrepo in parallel, it can help to avoid
race conditions caused by accessing or creating the same rpm database
by multiple createrepo instances at the same time.
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
