Fix a typo in "sample-create" help message
Fix a typo in "sample-create" help message

The word "alarm" is used twice instead of "sample".

Change-Id: I9a3ce514f3a3766add14ed1b352e31bf003f1cee

citrix-openstack-build/python-ceilometerclient,citrix-openstack-build/python-ceilometerclient