This change fixes a behavior that might be surprising to a
user: If a reject clause is configured for a pipeline, the reject clause
is always true even if no approval is set. If, however, an unrelated
approval is added to the change, the reject clause is evaluated as
expected.
The root cause was a check that assumed that the absence of approvals
will lead to a negative filter result. However, this is only true for
requirements.
Change-Id: I220bbed931ced7e807febefbf2b1b33af53a8da0