Use preinstalled OpenSSL

appveyor.yml

-version: 1.0.{build}
+version: 1.1.{build}
 image: Visual Studio 2015
 configuration: Debug
-install:
-- ps: cinst openssl.light -y
 build_script:
 - cmd: >-
     mkdir build.paho

src/CMakeLists.txt

@@ -114,7 +114,7 @@ IF (PAHO_WITH_SSL)
     ENDIF (${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
 
     IF (WIN32)
-      SET(OPENSSL_SEARCH_PATH "C:/Program Files/OpenSSL")
+      SET(OPENSSL_SEARCH_PATH "C:/OpenSSL-Win64")
     ENDIF ()
 
     FIND_PATH(OPENSSL_INCLUDE_DIR openssl/ssl.h