Buildsystem: Enforce Visual Studio 2015 Update 1 in CMake

Even if it's for few days, it looks it's absolute minimum needed to compile 3.3.5a for now

cmake/compiler/msvc/settings.cmake

@@ -1,10 +1,10 @@
 # set up output paths for executable binaries (.exe-files, and .dll-files on DLL-capable platforms)
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 
-set(MSVC_EXPECTED_VERSION 19.0)
+set(MSVC_EXPECTED_VERSION 19.00.23506)
 
 if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS MSVC_EXPECTED_VERSION)
-  message(FATAL_ERROR "MSVC: TrinityCore requires version ${MSVC_EXPECTED_VERSION} (MSVC 2015) to build but found ${CMAKE_CXX_COMPILER_VERSION}")
+  message(FATAL_ERROR "MSVC: TrinityCore requires version ${MSVC_EXPECTED_VERSION} (MSVC 2015 Update 1) to build but found ${CMAKE_CXX_COMPILER_VERSION}")
 endif()
 
 # set up output paths ofr static libraries etc (commented out - shown here as an example only)