ARROW-7736: [Release] Retry binary download on transient error

It makes binary verification more robust.

Closes #6335 from kou/release-verification-binaries-retry and squashes the following commits:

38944a9 <Sutou Kouhei>  Retry binary download on transient error

Authored-by: Sutou Kouhei <kou@clear-code.com>
Signed-off-by: Krisztián Szűcs <szucs.krisztian@gmail.com>

dev/release/download_rc_binaries.py

@@ -112,7 +112,7 @@ def _download_file(self, dest, info):
         bintray_abspath = os.path.join(BINTRAY_DL_ROOT, self.repo, relpath)
 
         cmd = [
-            'curl', '--fail', '--location',
+            'curl', '--fail', '--location', '--retry', '5',
             '--output', dest_path, bintray_abspath
         ]
         proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,