openssl: remove all uses of USE_SSLEAY

SSLeay was the name of the library that was subsequently turned into
OpenSSL many moons ago (1999). curl does not work with the old SSLeay
library since years. This is now reflected by only using USE_OPENSSL in
code that depends on OpenSSL.

CMakeLists.txt

@@ -298,7 +298,6 @@ endif()
 option(CMAKE_USE_OPENSSL "Use OpenSSL code. Experimental" ON)
 mark_as_advanced(CMAKE_USE_OPENSSL)
 
-set(USE_SSLEAY OFF)
 set(USE_OPENSSL OFF)
 set(HAVE_LIBCRYPTO OFF)
 set(HAVE_LIBSSL OFF)
@@ -307,7 +306,6 @@ if(CMAKE_USE_OPENSSL)
   find_package(OpenSSL)
   if(OPENSSL_FOUND)
     list(APPEND CURL_LIBS ${OPENSSL_LIBRARIES})
-    set(USE_SSLEAY ON)
     set(USE_OPENSSL ON)
     set(HAVE_LIBCRYPTO ON)
     set(HAVE_LIBSSL ON)
@@ -754,7 +752,6 @@ if(CMAKE_USE_OPENSSL)
     HAVE_CRYPTO_CLEANUP_ALL_EX_DATA)
   if(HAVE_LIBCRYPTO AND HAVE_LIBSSL)
     set(USE_OPENSSL 1)
-    set(USE_SSLEAY 1)
   endif(HAVE_LIBCRYPTO AND HAVE_LIBSSL)
 endif(CMAKE_USE_OPENSSL)
 check_symbol_exists(gmtime_r      "${CURL_INCLUDES}" HAVE_GMTIME_R)