Fix manual references to old alarm syntax

The ceilometerclient patch refered to in the bug report
changed the way ceilometerclient works to not require the
-a flag for certain alarm commands (history, show etc).

The CLI reference has already been updated, but this patch
fixes the remaining manually written commands

Change-Id: I2e00a6830cd0d4abaa2d37dfb3516bb52f13914b
Closes-Bug: 1268557
Merge "Fix manual references to old alarm syntax"