Log Message:
Restore support for apr0 via the SUGGESTED apr1 option.

Do not include logic to auto-enable apr1 if the option apache22 is
defined because apache22 does not appear to be a valid option.

Do not force apr1 if serf is selected.  Instead, fail and force the
user to choose consistent options.

No PKGREVISION because apr1 is the default and the resulting package
is unchanged.  apr0 support not tested.