Update test-birfrost to limit log lines
Update test-birfrost to limit log lines

test-birfrost notes that only the last 1000 lines of some log files
will be output, but uses cat to dump the entire file. This patch limits
output to 1000 lines.

Change-Id: I02fce16edd9d1494a7bee3c534db4c264923a12d

openstack/bifrost,devananda/bifrost,bcornec/bifrost,EntropyWorks/bifrost,EntropyWorks/bifrost,bcornec/bifrost,devananda/bifrost,openstack/bifrost