clientv3/integration: do not run fragmentation tests with gRPC Proxy
clientv3/integration: do not run fragmentation tests with gRPC Proxy

Signed-off-by: Gyuho Lee <3454051ee3341eb69bdf6fca40899cdad4d86496@gmail.com>

coreos/etcd,bdarnell/etcd,sinsharat/etcd,xiang90/etcd,rnaveiras/etcd,xiang90/etcd,rnaveiras/etcd,sebrandon1/etcd,mqliang/etcd,gyuho/etcd,glevand/coreos--etcd,etcd-io/etcd,ajityagaty/etcd,mkumatag/etcd,mkumatag/etcd,bdarnell/etcd,mkumatag/etcd,coreos/etcd,li-ang/etcd,sinsharat/etcd,mqliang/etcd,joshix/etcd,li-ang/etcd,rnaveiras/etcd,gyuho/etcd,cockroachdb/etcd,vimalk78/etcd,vimalk78/etcd,ajityagaty/etcd,mqliang/etcd,dannysauer/etcd,joshix/etcd,glevand/coreos--etcd,dannysauer/etcd,etcd-io/etcd,cockroachdb/etcd,etcd-io/etcd,ajityagaty/etcd,sebrandon1/etcd