use the ones shiped from the latest cmake. which
* enables us to find the recent python intepreter and development files,
* find intepreter and development in a single `find_pacakge()` command,
simpler this way and less error prone.
and to accomodate this change:
* all `PYTHON${PYTHON_VERSION}_*` variables are renamed to
`Python${PYTHON_VERSION}_*` if we use `find_package(Python2...)` or
`find_package(Python3...)` to find python2 or python3 instead of using
`find_package(Python...)`.
* use "2" explicitly when using python2, as `Python_*` variables are not
defined anymore
* when compiling python support of ceph-mgr, continue using `Python_*`
variables. because we find the python interpreter and development
files using `find_pacakge(Python...)` for ceph-mgr.
Signed-off-by: Kefu Chai <kchai@redhat.com>
