bitbake: process: Do not mix stderr with stdout

We should not redirect stderr to stdout if we need to get separated
stdout and stderr contents from Popen.communicate() later.

(Bitbake rev: eef2355331e7e03b2c7615695694c5ba9877fb36)

Signed-off-by: Anton Mikanovich <amikan@ilbers.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 1ecc1d9424877df89fcda2f23c306998998a65ff)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/process.py

@@ -60,7 +60,7 @@ class Popen(subprocess.Popen):
         "close_fds": True,
         "preexec_fn": subprocess_setup,
         "stdout": subprocess.PIPE,
-        "stderr": subprocess.STDOUT,
+        "stderr": subprocess.PIPE,
         "stdin": subprocess.PIPE,
         "shell": False,
     }