Currently folks end up using os.chdir() (see bug listed below) as
we are not exposing the subprocess.Popen's cwd parameter. It's
better to add a cwd parameter in processutils.execute so folks
do not have to issue chdir() before and after the processutils.
execute and there's less scope for problem as documented in
the bug.
Closes-Bug: #1414530
Change-Id: Ia4c77593c0f8301e059b349290e8663614a7ccfd