global resp cause check panic

[woniu317]

var resp *http.Response

func testGlobal() {
	resp, _ = http.Get("https://example.com")
	resp.Body.Close()

}

It cause panic when check this code.

ERRO [runner] Panic: bodyclose: package "main" (isInitialPkg: true, needAnalyzeSource: true): runtime error: invalid memory address or nil pointer dereference: goroutine 4224 [running]:
runtime/debug.Stack()
	runtime/debug/stack.go:24 +0x65
github.com/golangci/golangci-lint/pkg/golinters/goanalysis.(*action).analyzeSafe.func1()
	github.com/golangci/golangci-lint/pkg/golinters/goanalysis/runner_action.go:101 +0x155
panic({0x4aeda60, 0x557d2c0})
	runtime/panic.go:1038 +0x215
github.com/timakin/bodyclose/passes/bodyclose.(*runner).isopen(0xc003c2dd08, 0xc01d94f770, 0x4)
	github.com/timakin/bodyclose@v0.0.0-20200424151742-cb6215831a94/passes/bodyclose/bodyclose.go:135 +0x18d
github.com/timakin/bodyclose/passes/bodyclose.runner.run({0xc014270f70, {0x4e5caf8, 0xc0024143c0}, 0xc01d94f770, {0x4e5cb98, 0xc0024145f0}, 0xc000da2640, 0xc01b888a20}, 0xc014270f70)
	github.com/timakin/bodyclose@v0.0.0-20200424151742-cb6215831a94/passes/bodyclose/bodyclose.go:102 +0x5c5
github.com/golangci/golangci-lint/pkg/golinters/goanalysis.(*action).analyze(0xc0003b4300)
	github.com/golangci/golangci-lint/pkg/golinters/goanalysis/runner_action.go:187 +0x9c4
github.com/golangci/golangci-lint/pkg/golinters/goanalysis.(*action).analyzeSafe.func2()
	github.com/golangci/golangci-lint/pkg/golinters/goanalysis/runner_action.go:105 +0x1d
github.com/golangci/golangci-lint/pkg/timeutils.(*Stopwatch).TrackStage(0xc001a0e8c0, {0x4c2232d, 0x9}, 0xc002c0d760)
	github.com/golangci/golangci-lint/pkg/timeutils/stopwatch.go:111 +0x4a
github.com/golangci/golangci-lint/pkg/golinters/goanalysis.(*action).analyzeSafe(0xc0003b4300)
	github.com/golangci/golangci-lint/pkg/golinters/goanalysis/runner_action.go:104 +0x85
github.com/golangci/golangci-lint/pkg/golinters/goanalysis.(*loadingPackage).analyze.func2(0x0)
	github.com/golangci/golangci-lint/pkg/golinters/goanalysis/runner_loadingpackage.go:80 +0x67
created by github.com/golangci/golangci-lint/pkg/golinters/goanalysis.(*loadingPackage).analyze
	github.com/golangci/golangci-lint/pkg/golinters/goanalysis/runner_loadingpackage.go:75 +0x1fd