Revert "Set CEILOMETER_PIPELINE_INTERVAL to 15"

This reverts commit e9aa963b5eac7c841a5adeb86437c3823a4e47d3.

Change-Id: I7d3e76f138a52a30a0d609899b78f2d53119f812
Merge "Revert "Set CEILOMETER_PIPELINE_INTERVAL to 15""