Remove print debugs statements.

Change-Id: I78a885ba98363ca309598294bc84604d05a55446
return sample info when creating sample with CLI

It will return nothing after creating a sample successfully with
ceilometer CLI. The information of the sample created should be return,
like other creating commands, such as "ceilometer alarm-create".

Change-Id: I60229fefa91de83e4b715cf4f92d3650e0a0d162
Closes-bug: #1267713
Using common methods from oslo cliutils

There are some common methods in cliutils we can use in ceilometerclient:
arg, env, unauthenticated, isunauthenticated.

+ Replaces utils.env to add alias env from cliutils.
+ Removes unused methods in utils: env
To use methods from clituils.

partially implements blueprint common-client-library-2

Change-Id: I295cc80635ed15c91e2832acb315e9deede09516
Remove ununsed httplib2 requirement

This is not needed anymore since the logging is handled by
six.moves/httplib.

Change-Id: I4de3cfd8d8d3c08b38e39fde12172bdb4de0cea0
Closes-Bug: 1272986
Merge "Using common methods from oslo cliutils"
Merge "return sample info when creating sample with CLI"
Merge "Remove print debugs statements."
Merge "Remove ununsed httplib2 requirement"