msvc: Fix an "unrecognized option" linker warning

msvc: Fix an "unrecognized option" linker warning

Having recently added support for building git-imap-send on
Windows, we now link against OpenSSL libraries, and the linker
issues the following warning:

    warning LNK4044: unrecognized option '/lssl'; ignored

In order to suppress the warning, we change the msvc linker
script to translate an '-lssl' parameter to the ssleay32.lib
library.

Note that the linker script was already including ssleay32.lib
(along with libeay32.lib) as part of the translation of the
'-lcrypto' library parameter.  However, libeay32.dll does not
depend on ssleay32.dll and can be used stand-alone, so we remove
ssleay32.lib from the '-lcrypto' translation.

The dependence of ssleay32.dll on libeay32.dll is represented in
the Makefile by the NEEDS_CRYPTO_WITH_SSL build variable.

Also, add the corresponding change to the buildsystem generator.

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Acked-by: Sebastian Schuberth <sschuberth@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>