Remove buggy assert() on vclock_get() result
Remove buggy assert() on vclock_get() result

vclock_get() can return -1 in this case.
Probably introduced by 311551f98a090fc1240a661e728fc4322f370b14

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