Bug report

Required Info:

• Operating System:
  • Ubuntu 18.04 (should happen in any)
• Installation type:
  • from source (should happen in any)
• Version or commit hash:
  • master
• DDS implementation:
  • N/A
• Client library (if applicable):
  • N/A

Steps to reproduce issue

ros2 security generate_artifacts -k tmp -n /node1 /ns/node1 /ns/node2
ros2 security list_keys tmp

Expected behavior

Output:

/node1
/ns/node1
/ns/node2

Actual behavior

Output:

node1
ns

Additional information

This should be fixed for Dashing/Eloquent, and also for Foxy after #177 is merged.
Add a regression test too.