Clarify the help text for error_wait_time
Clarify the help text for error_wait_time

The help text for error_wait_time is identical to stack_action_timeout
and does not indicate what it actually controls.

Change-Id: I1e7eeb3586e70b668534ed2fd6c8a45ec4c625fd

steveb/heat,openstack/heat,noironetworks/heat,cwolferh/heat-scratch,cwolferh/heat-scratch,noironetworks/heat,openstack/heat,steveb/heat