releasetools: Set default stdout and stderr in common.Run().

stdout and stderr will default to subprocess.PIPE and subprocess.STDOUT
respectively (which is the expected behavior from most of the existing
callers), unless caller specifies any of them.

Test: `m dist`
Test: python -m unittest \
          test_common \
          test_add_img_to_target_files \
          test_ota_from_target_files \
          test_validate_target_files
Change-Id: I43b3f08edfa8a9bcfe54baf9848dc705c048e327

tools/releasetools/validate_target_files.py

@@ -35,7 +35,6 @@ import filecmp
 import logging
 import os.path
 import re
-import subprocess
 import zipfile
 
 import common
@@ -256,7 +255,7 @@ def ValidateVerifiedBootImages(input_tmp, info_dict, options):
         continue
 
       cmd = ['boot_signer', '-verify', image_path, '-certificate', verity_key]
-      proc = common.Run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+      proc = common.Run(cmd)
       stdoutdata, _ = proc.communicate()
       assert proc.returncode == 0, \
           'Failed to verify {} with boot_signer:\n{}'.format(image, stdoutdata)
@@ -299,7 +298,7 @@ def ValidateVerifiedBootImages(input_tmp, info_dict, options):
         continue
 
       cmd = ['verity_verifier', image_path, '-mincrypt', verity_key_mincrypt]
-      proc = common.Run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+      proc = common.Run(cmd)
       stdoutdata, _ = proc.communicate()
       assert proc.returncode == 0, \
           'Failed to verify {} with verity_verifier (key: {}):\n{}'.format(
@@ -328,7 +327,7 @@ def ValidateVerifiedBootImages(input_tmp, info_dict, options):
             partition, info_dict, options[key_name])
         cmd.extend(["--expected_chain_partition", chained_partition_arg])
 
-    proc = common.Run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    proc = common.Run(cmd)
     stdoutdata, _ = proc.communicate()
     assert proc.returncode == 0, \
         'Failed to verify {} with verity_verifier (key: {}):\n{}'.format(