cmake: working on cephtool-test-rados.sh test

cmake: working on cephtool-test-rados.sh test

Replaced relative paths in test/cephtool-test-rados.sh,
qa/workunits/rados/test_rados_tool.sh,
src/test/vstart_wrapper.sh, with CEPH_FOO environment
variables set in cmake. Also edited the CMake path
finding logic in vstart.sh with the CEPH_FOO variables.

NOTE: test is not passing yet, possibly due to the
filesystem. this commit is a work in progress

Signed-off-by: Ali Maredia <amaredia@redhat.com>