Add expected RangeDescriptor to AdminChangeReplicas and adopt#36244

Merged

craig[bot] merged 2 commits intocockroachdb:masterfrom ajwerner:ajwerner/admin-change-replicas-exp-desc

Mar 30, 2019

+1,494-1,009

Commits on Mar 29, 2019

roachpb: add ExpDesc to AdminChangeReplicas and updated value to response
ajwerner
committed

Commits on Mar 30, 2019

client,storage: adopt ExpDesc in AdminChangeReplicas and use in RelocateRange
ajwerner
committed