cmake: update fio version from 3.5 to 540e235dcd276e63c57.

cmake: update fio version from 3.5 to 540e235dcd276e63c57.

Fio commit(d04f1d5b342e7733) make external ioengine work.
This need when build libfio_ceph_objectstore.so.

Meanwhile fix a comiler error:
/home/ceph/src/test/fio/fio_ceph_objectstore.cc: In constructor ‘{anonymous}::ceph_ioengine::ceph_ioengine()’:
/home/ceph/src/test/fio/fio_ceph_objectstore.cc:733:19: error: invalid conversion from ‘int (*)(thread_data*, io_u*)’ to ‘fio_q_status (*)(thread_data*, io_u*)’ [-fpermissive]
     queue       = fio_ceph_os_queue;
                   ^~~~~~~~~~~~~~~~~
src/test/fio/CMakeFiles/fio_ceph_objectstore.dir/build.make:62: recipe for target 'src/test/fio/CMakeFiles/fio_ceph_objectstore.dir/fio_ceph_objectstore.cc.o' failed

Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>