Merge pull request #12 from ndibari-etsy/reorder_error_check_on_relea…

…se_download

fix: check err before using file object

internal/releaseapi/client.go

@@ -161,17 +161,20 @@ func (c *Client) downloadBuild(build Build, checkSha256Sum string) (string, erro
  log.Printf("dowloading release archive from %s", build.URL)
 
  zipFile, zipLength, err := c.downloadReleaseArchive(build)
- defer os.Remove(zipFile.Name())
- defer zipFile.Close()
 
  if err != nil {
  return "", err
  }
 
+ defer os.Remove(zipFile.Name())
+ defer zipFile.Close()
+
  f, err := os.Open(zipFile.Name())
+
  if err != nil {
  return "", errors.Wrap(err, "could not open zip archive")
  }
+
  defer f.Close()
 
  h := sha256.New()