Purposing patch for groonga engine's CMakeList

This purposed patch contains ( if not defined ) conditions inside of the groonga's and groonga-normalizer-mysql CMakeLists for the install path.

Reason for this patch is that if groonga package is packaged separately, while installing it the conflict occurs between the installed files from mariadb-server.

With this patch you have to only include two options to cmake and conflict is gone.