See http://bugzilla.gnome.org/show_bug.cgi?id=335386. I have included this patch into the gnome-extra/evolution-data-server ebuild. Download my patch from the attachment go to /usr/portage and run `patch -p1 < <path_to_my_patch>`. My patch puts the original patch to gnome-extra/evolution-data-server/files and adds a corresponding epatch call to gnome-extra/evolution-data-server/evolution-data-server-1.6.2.ebuild.
Created attachment 94054 [details, diff] Adds a patch to make evolution work with gpg and smartcard to the evolution-data-server ebuild.
Upstream bug report was closed stating: "fixed in the 2.7 branch (HEAD), changes strings so can't apply it to stable branch" Now we have 2.8 stable. I think this should be fixed. Reopen, please, if I'm wrong.