vinyl: patch holes in index on recovery
vinyl: patch holes in index on recovery

Successful compaction may create a range w/o tuples, and currently we
don't store empty range files on disk. As a result, such a range won't
be loaded on recovery, which breaks the index tree invariant (prev->end
equals next->begin). Hence we must silently create a new range for each
gap found on recovery.

rtsisyk/tarantool,mejedi/tarantool,rtsisyk/tarantool,mejedi/tarantool,rtsisyk/tarantool,mejedi/tarantool,rtsisyk/tarantool,mejedi/tarantool