The post-install information for this ebuild shows how to use revdep-rebuild to make removal of the libs safe. However, I have openssh installed as well, and it turned out that I could not login to my SSH server after removing the openssl-0.9.7 libraries (after doing the revdep-rebuild, of course). I'm not sure why revdep-rebuild didn't catch that stuff, but the note should probably be expanded to include this information. (I solved this by re-emerging openssh.)
*** This bug has been marked as a duplicate of 147956 ***