Fix variable name and clarify version check

Author: wravery

samples/CMakeLists.txt

@@ -11,10 +11,14 @@ add_subdirectory(validation)
 if(GRAPHQL_BUILD_HTTP_SAMPLE)
   find_package(Boost QUIET)
   if(Boost_FOUND)
-    if(Boost_VERSIION VERSION_GREATER_EQUAL "1.81.0" AND EXISTS "${Boost_INCLUDE_DIR}/boost/beast.hpp")
-      add_subdirectory(proxy)
+    if(Boost_VERSION VERSION_GREATER_EQUAL "1.81.0")
+      if(EXISTS "${Boost_INCLUDE_DIR}/boost/beast.hpp")
+        add_subdirectory(proxy)
+      else()
+        message(WARNING "GRAPHQL_BUILD_HTTP_SAMPLE requires the Boost.Beast header-only library, but it was not found in ${Boost_INCLUDE_DIR}.")
+      endif()
     else()
-      message(WARNING "GRAPHQL_BUILD_HTTP_SAMPLE requires the Boost.Beast header-only library >= 1.81.0, but it was not found in ${Boost_INCLUDE_DIR}.")
+      message(WARNING "GRAPHQL_BUILD_HTTP_SAMPLE requires the Boost.Beast header-only library >= 1.81.0, but only ${Boost_VERSION} was found in ${Boost_INCLUDE_DIR}.")
     endif()
   endif()
 endif()