common/ceph_mutex: ceph::{mutex,condition_variable,lock_guard}

common/ceph_mutex: ceph::{mutex,condition_variable,lock_guard}

If CEPH_DEBUG_MUTEX is defined, use the [recursive_]mutex_debug classes
that implement lockdep and a bucnh of other random debug checks.  Also
typedef ceph::condition_variable to std::condition_variable_debug, which
adds addition assertions and debug checks.

If CEPH_DEBUG_MUTEX is not defined, then use the bare-bones C++ std::mutex
primitives... or as close as we can get to them.

Since the [recursive_]mutex_debug classes take a string argument for the
lockdep piece, define factory functions ceph::make_[recursive_]mutex that
either pass arguments to the debug implementations or toss them out.

Signed-off-by: Sage Weil <sage@redhat.com>