CA-403474: Improve check before pool eject

[xueqingz]

test result:

ubuntu@ubuntu-server:~/code/terraform-provider-xenserver$ make testacc
if [ -z "/home/ubuntu/go/bin" ]; then echo "GOBIN is not set" && exit 1; fi
rm -f /home/ubuntu/go/bin/terraform-provider-xenserver
go mod tidy
go install .
md5sum /home/ubuntu/go/bin/terraform-provider-xenserver
d21a70147473c4fc9c6a97ab6a3bed3e  /home/ubuntu/go/bin/terraform-provider-xenserver
source .env \
    && TF_ACC=1 go test -v  -timeout 60m ./xenserver/ \
    && TF_ACC=1 TEST_POOL=1 go test -v -run TestAccPoolResource -timeout 60m ./xenserver/
=== RUN   TestAccHostDataSource
--- PASS: TestAccHostDataSource (1.20s)
=== RUN   TestAccNetworkDataSource
--- PASS: TestAccNetworkDataSource (0.69s)
=== RUN   TestAccVlanResource
--- PASS: TestAccVlanResource (4.47s)
=== RUN   TestAccNICDataSource
--- PASS: TestAccNICDataSource (0.68s)
=== RUN   TestAccPIFConfigureResource
--- PASS: TestAccPIFConfigureResource (18.81s)
=== RUN   TestAccPifDataSource
--- PASS: TestAccPifDataSource (1.23s)
=== RUN   TestAccPoolResource
    pool_resource_test.go:108: Skipping TestAccPoolResource test due to TEST_POOL not set
--- SKIP: TestAccPoolResource (0.00s)
=== RUN   TestAccSnapshotResource
--- PASS: TestAccSnapshotResource (7.06s)
=== RUN   TestAccSRDataSource
--- PASS: TestAccSRDataSource (0.72s)
=== RUN   TestAccNFSResource
--- PASS: TestAccNFSResource (4.36s)
=== RUN   TestAccNFSISOResource
--- PASS: TestAccNFSISOResource (3.80s)
=== RUN   TestAccSRResourceLocal
--- PASS: TestAccSRResourceLocal (4.27s)
=== RUN   TestAccSRResourceShared
--- PASS: TestAccSRResourceShared (3.56s)
=== RUN   TestAccSMBResource
--- PASS: TestAccSMBResource (3.77s)
=== RUN   TestAccSMBISOResource
--- PASS: TestAccSMBISOResource (3.70s)
=== RUN   TestAccVDIResource
--- PASS: TestAccVDIResource (5.12s)
=== RUN   TestAccVMDataSource
--- PASS: TestAccVMDataSource (2.40s)
=== RUN   TestAccVMResource
--- PASS: TestAccVMResource (5.11s)
=== RUN   TestAccLinuxVMResource
--- PASS: TestAccLinuxVMResource (2.32s)
PASS
ok      terraform-provider-xenserver/xenserver  73.288s

ubuntu@ubuntu-server:~/code/terraform-provider-xenserver$ make testpool
if [ -z "/home/ubuntu/go/bin" ]; then echo "GOBIN is not set" && exit 1; fi
rm -f /home/ubuntu/go/bin/terraform-provider-xenserver
go mod tidy
go install .
md5sum /home/ubuntu/go/bin/terraform-provider-xenserver
f9bc8818e761c2304a5e1bd22c4e117d  /home/ubuntu/go/bin/terraform-provider-xenserver
source .env \
&& TF_ACC=1 TEST_POOL=1 go test -v -run TestAccPoolResource -timeout 60m ./xenserver/
=== RUN   TestAccPoolResource
--- PASS: TestAccPoolResource (47.14s)