Buildsystem/CMake: Revert changes from r0fa0512527 and use the proper checks (fix logic-error in buildfile)

--HG--
branch : trunk

CMakeLists.txt

@@ -12,7 +12,6 @@ project(TrinityCore)
 
 # CMake policies
 cmake_minimum_required(VERSION 2.6)
-cmake_policy(SET CMP0002 OLD)
 cmake_policy(SET CMP0005 OLD)
 
 #

src/server/CMakeLists.txt

@@ -17,7 +17,8 @@ if( SERVERS )
     add_subdirectory(scripts)
   endif()
   add_subdirectory(worldserver)
-endif()
-if( TOOLS )
-  add_subdirectory(collision)
+else()
+  if( TOOLS )
+    add_subdirectory(collision)
+  endif()
 endif()