sys-apps/portage: fix Ctrl-C CancelledError regression (bug 657436)

sys-apps/portage: fix Ctrl-C CancelledError regression (bug 657436)

Fix an annoying regression involving a CancelledError exception raised
during Ctrl-C interrupt handling. Also include the small patch for
bug 657420. Remove the sed call that applied commit d07a47ff3c06 for
bug 656942, and apply the fix using a patch instead.

See: https://gitweb.gentoo.org/proj/portage.git/commit/?id=937d0156aa060bdba9095313dedbb62e0a993aea
See: https://gitweb.gentoo.org/proj/portage.git/commit/?id=9e07f3a45c1b321edd07530b278498cb09f8983c
See: https://gitweb.gentoo.org/proj/portage.git/commit/?id=1fc628eead43fa5da4b142479aa004ded8acceab
Closes: https://bugs.gentoo.org/657436
See: https://gitweb.gentoo.org/proj/portage.git/commit/?id=e8067a8e6fbdaccca5915e66c77518e82b090401
Closes: https://bugs.gentoo.org/657420
Package-Manager: Portage-2.3.40, Repoman-2.3.9