Fix a bug with non-working removal of a failed snapshot.
Fix a bug with non-working removal of a failed snapshot.

Remove the snapshot in abort_checkpoint(). Use coeio_remove/coeio_unlink
bindings instead of coeio_custom().

dkorolev/tarantool,vasilenkomike/tarantool,rtsisyk/tarantool,mejedi/tarantool,ocelot-inc/tarantool,condor-the-bird/tarantool,KlonD90/tarantool,nvoron23/tarantool,mejedi/tarantool,condor-the-bird/tarantool,condor-the-bird/tarantool,guard163/tarantool,ocelot-inc/tarantool,KlonD90/tarantool,vasilenkomike/tarantool,dkorolev/tarantool,vasilenkomike/tarantool,rtsisyk/tarantool,Sannis/tarantool,Sannis/tarantool,guard163/tarantool,condor-the-bird/tarantool,nvoron23/tarantool,Sannis/tarantool,dkorolev/tarantool,Sannis/tarantool,mejedi/tarantool,dkorolev/tarantool,nvoron23/tarantool,guard163/tarantool,guard163/tarantool,nvoron23/tarantool,nvoron23/tarantool,KlonD90/tarantool,mejedi/tarantool,rtsisyk/tarantool,condor-the-bird/tarantool,Sannis/tarantool,guard163/tarantool,dkorolev/tarantool,ocelot-inc/tarantool,vasilenkomike/tarantool,ocelot-inc/tarantool,vasilenkomike/tarantool,nvoron23/tarantool,KlonD90/tarantool,rtsisyk/tarantool,KlonD90/tarantool