buildhistory: Use bb.utils.mkdirhier instead of os.makedirs

:Release Notes:
Multiple do_fetch[prefunc] can happen at the same time and
if not os.path.exists(pkghistdir):
    os.makedirs(pkghistdir)
isn't safe

:Detailed Notes:
Use bb.utils.mkdirhier which doesn't raise error when directory exists

:Testing Performed:
Build tested only, but I wasn't able to reproduce this race before

:QA Notes:

:Issues Addressed:
[GF-9987] Strange failure when building depmodwrapper-cross

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I62e2f0930c0f94af962af96b9dcaf51dff073938
Reviewed-on: https://g2g.palm.com/2900
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Build Verification
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>