Clean up connectivity script.

This CL cleans up the 'connectivity' script. It also adds 'connectivity
show-feedback', which is similar to 'connectivity show' but tailors
output for feedback reports.

BUG=chromium-os:33198
TEST=Tested the following commands:
1. `connectivity show devices`
2. `connectivity show devices -filter eth0`
3. `connectivity show services`
4. `connectivity show-feedback devices`
5. `connectivity show-feedback services`

Change-Id: If3ac702bfb733b7264c3bde58e9cdffe334fbd4a
Reviewed-on: https://gerrit.chromium.org/gerrit/29106
Reviewed-by: Thieu Le <thieule@chromium.org>
Commit-Ready: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
2 files changed