cpt-export: use sed to generate manifest

Testing the boost package, using sed results in a significant reduction
for argument generation instead of using the 'read' function. Below are
the 'time' stats for the script.

Previous:
real    0m 58.95s
user    0m 55.80s
sys     0m 3.54s

Current:
real    0m 0.66s
user    0m 0.78s
sys     0m 0.27s

FossilOrigin-Name: 80d891e830579822317d30b66b1b019828fca9343ada23ce17585622288deef3

0 files changed, 0 insertions, 0 deletions