Revert "autotools: don't link with -lcrypto twice."

Revert "autotools: don't link with -lcrypto twice."

This reverts commit 036fa9c7b8be4bda360a1075427b3b2420a92986.

That doesn't work.  We'd have to figure out what -I flag to use with
that version of libcrypto and set the CFLAGS appropriately, and set
HAVE_LIBCRYPTO to yes.

If you have more than one non-system version of a library, hilarity is
likely to ensure.  Don't do that.