Add oneshot support to count conditions

When a count condition is a oneshot, it will only
trigger the callback the first time the condition
is true.  The condition needs to evaluate to false
at least once to rearm the callback.

A use case for this would be when a group of properties
is being watched for a subset of them hit a certain value.
Even though every properties changed signal for every property
in the group would check the condition, only the first time
the condition is true would the callback be issued.

This behavior is specified with a 'oneshot: true' entry in
the YAML.  If not present, it defaults to false which is
the original behavior.

Tested: Verify this does indeed do what is advertised by
        modifying condition rules to consistently pass
        and checking behavior.

Change-Id: Ie185621e86c605234bf329a5f38317267dbb6fb6
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
5 files changed