Fix ceilometer.conf.sample mismatch

ceilometer.conf.sample mismatch issue makes the tests failing. This patch
removes the checkupdate.sh test from tox.ini, like it was removed from nova
too, until having a proper solution for handling the changes in
ceilometer.conf.sample, to fix the gate quickly.

Closes-Bug: #1297999

(cherry picked from commit 63ff15ed95f71f5272c64b82ff148d35f75782d4)

Conflicts:

	tox.ini
Change-Id: Ia638fb19ce25788a418b59509ec3527e643aac4e