Add 'info' command for showing package name, repo name, and source directory of ebuilds.
Add 'info' command for showing package name, repo name, and source directory of ebuilds.

BUG=chromium-os:5932, chromium-os:6126
TEST=Run cros_workon --all --host info and cros_workon info --host power_manager kernel

Change-Id: I46849db55d9879cbd65b4400eea9fd6b697e0a10
Reviewed-on: http://gerrit.chromium.org/gerrit/861
Reviewed-by: Zdenek Behan <483cf2a9a4e071d4fd973db6a5a78c40f490667c@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>

marineam/coreos-dev-util,marineam/coreos-dev-util,coreos/dev-util,coreos/dev-util,mgireesh05/dev-util,mgireesh05/dev-util,mgireesh05/dev-util,coreos/dev-util