Fix build with golangci-lint 1.54.2

[mtrmac]

Currently that fails with:

storage/storage_test.go:183:11: SA5011: possible nil pointer dereference (staticcheck)
		spec := ref.StringWithinTransport()
		        ^
storage/storage_test.go:188:6: SA5011(related information): this check suggests that the pointer can be nil (staticcheck)
		if ref == nil {

which is a real bug; and

storage/storage_test.go:183:11: SA5011: possible nil pointer dereference (staticcheck)
		spec := ref.StringWithinTransport()
		        ^
storage/storage_test.go:180:6: SA5011(related information): this check suggests that the pointer can be nil (staticcheck)
		if ref == nil {

which is a false positive, AFAICS.

See individual commit messages for details; one of them is just a workaround, but it seems worth doing anyway.

[rhatdan]

LGTM