be core down when add partition with buckets=0

[xionglei0]

doris support buckets = 0 while execute add partition statment like below:

then the be core down when loading data into the partition:
look at line 590, partition->num_buckets=0 and then core down

core like below:

so add bucket limit, and not support set buckets=0 while add partition:

[xionglei0]

#1855

[imay]

@xionglei0
We should close issue after PR is merged in master.