depgraph: respect <foo-version:= for slot operator rebuild (bug 717140)

When searching for slot operator rebuilds, respect non slot-operator
components of parent dependencies, so that a <foo-version:= dependency
like the <dev-libs/libgit2-1:0=[ssh?] dependency from bug 717140 will
not be completely ignored. This will prevent erroneous attempts to
trigger slot operator rebuilds for upgrades that would break
<foo-version:= dependencies (which triggered upgrade/downgrade loops
when backtracking tried to resolve the breakage).

Fixes: d569a2d7275c ("_slot_operator_update_probe: fix bug #508762")
Bug: https://bugs.gentoo.org/717140
Signed-off-by: Zac Medico <zmedico@gentoo.org>
2 files changed