net-firewall/iptables: restore compatibility with EAPI 7

Convert eselect-iptables dependency from EAPI's IDEPEND to
the old logic. This way iptables module correctly installed to
the SDK.

BUG=b/278627330,b/278136734,b/278627283,b/278802165
TEST=presubmit
RELEASE_NOTE=None

Change-Id: Iba61a33210c5a60adf9029cb638cc8b1f69039cb
Reviewed-on: https://cos-review.googlesource.com/c/third_party/overlays/portage-stable/+/47869
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
2 files changed