Remove the option of using libcrypto.

Remove the option of using libcrypto.

This scorches the earth and waits for spring;
see Ted Zlatanov and Stefan Monnier in
<http://lists.gnu.org/archive/html/emacs-devel/2013-12/msg00323.html>.
* configure.ac (with_openssl_default, HAVE_LIB_CRYPTO): Remove.
Do not say whether Emacs is configured to use a crypto library,
since it's no longer an option.
(gl_CRYPTO_CHECK): Define a dummy.
* lib/gl_openssl.h, m4/gl-openssl.m4: Remove.
* admin/merge-gnulib: Remove lib/gl_openssh.h and m4/gl-openssl.m4.
* src/Makefile.in (LIB_CRYPTO): Remove.
(LIBES): Don't use it.