Fix buildbot errors (associated with libiberty).
Cherry-pick pieces of odnoklassniki patch (patch is credits to @yuran)

This patch implements show index and shows memory waste of the
slab allocator.
Merge branch 'stable' of github.com:tarantool/tarantool into stable
Merge remote-tracking branch 'origin/stable'

Conflicts:
	src/admin.cc
	src/admin.rl
	src/box/bitset_index.cc
	src/box/hash_index.cc
	src/box/hash_index.h
	src/box/space.cc
	src/box/space.h
	test/box/admin.result