buildhistory create .txt file bh_installed_pkgs.txt and
bh_installed_pkgs_deps.txt while listing down installed package.
These file is later removed in buildhistory_get_installed().
when multiple process runs in parellal there are chances to race for
the file where one process created the file while another task remove
the file right after it.
using different file name for each process should avoid the race. So
add PID to the file name to make it unique.
[yocto #13709]
Signed-off-by: Lee Chee Yang <chee.yang.lee@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
