gh-183: review fixes. Use a RAII class for scoped guard.
gh-183: review fixes. Use a RAII class for scoped guard.

Remove an extra block offset.

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