CryptoPkg: Fix capitalization of path name in Patch-HOWTO.txt

It's "OpensslLib", not "OpenSslLib" - not a big issue, but the
typo is annoying when trying to copy-n-paste the path name to
use it on the command line on Linux.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Qin Long <qin.long@intel.com>
Reviewed-By: Wu Jiaxin <jiaxin.wu@intel.com>