Changed: Allow to compile Ryzom tools even without MySQL (mysql client library has compilation problems with VC++ 2015)

--HG--
branch : develop

code/ryzom/CMakeLists.txt

@@ -13,6 +13,8 @@ ADD_SUBDIRECTORY(client)
 IF(WITH_RYZOM_SERVER OR WITH_RYZOM_TOOLS)
   # Need servershare for build packed collision tool
   # Need aishare for build wmap tool
-  FIND_PACKAGE(MySQL REQUIRED)
+  FIND_PACKAGE(MySQL)
+  IF(MYSQL_FOUND)
     ADD_SUBDIRECTORY(server)
   ENDIF()
+ENDIF()