make-flight: configure host_suite=wheezy runvar for armhf runs
Otherwise: http://www.chiark.greenend.org.uk/~xensrcts/logs/19744/build-armhf/3.ts-xen-build-prep.log:
2013-09-19 11:09:37 Z host: selected army <unknown-ether> 10.80.246.74 - shared build-wheezy-armhf
0073b3e489cf150d3f1c4eb3f3a4f942197f0932 prep 1
resource host army shared build-wheezy-armhf
0073b3e489cf150d3f1c4eb3f3a4f942197f0932 not build-squeeze-armhf
0073b3e489cf150d3f1c4eb3f3a4f942197f0932 at Osstest/Executive.pm line 608.
+ rc=255