Add the getBuildArch() function which does what this was doing in
buildinstall:
repoquery -c CONF --qf "%{ARCH}\n" anaconda
Also fixed the mkstemp() usage.
This functionality was previously handled by the makestamp.py
script in anaconda. Created a module under pylorax with just
one function (for now). Not sure if it will need to be
extended, but part of the reason for rewriting all of this
code is to make it more extendable.
