sys-apps/portage: 2.3.78-r2 revbump for bug 698046

sys-apps/portage: 2.3.78-r2 revbump for bug 698046

This avoids confusing "No such file or directory" errors as demonstrated
by the following test case:

$ ln -s /foo/bar /tmp/sudo-1.8.29rc1.tar.gz
$ wget http://distfiles.gentoo.org/distfiles/sudo-1.8.29rc1.tar.gz -O /tmp/sudo-1.8.29rc1.tar.gz
/tmp/sudo-1.8.29rc1.tar.gz: No such file or directory

Bug: https://bugs.gentoo.org/697734
Bug: https://bugs.gentoo.org/698046
Package-Manager: Portage-2.3.78, Repoman-2.3.17
Signed-off-by: Zac Medico <zmedico@gentoo.org>