security/libssh2: fix the GCRYPT option

The port uses the old crypto configure flags:
--with-libgcrypt and --with-openssl. These flags
are no longer supported.

Besides from the obvious effect of the actual port configuration
not matching user intent, it also produces incorrect pkg-config
file for the given set of dependencies, and other ports that
depend on libssh2 fail when it's configured with GCRYPT=on.

Fix by using the proper configure arguments:
--with-crypto=libgcrypt and --with-crypto=openssl.

PR: 248164
Submitted by: dgilbert@eicat.ca (bug report), James French (patch)
Approved by: maintainer timeout