opkg does not return a non-zero exit code even if it found
errors. When that happens, parsing the output leads to strange
follow-up errors.
To avoid this we need to check explicitly for non-empty
stderr. Reporting only that on a failure also leads to shorter error
messages (stdout may be very large).
(From OE-Core rev: 7d9e915224a9bc451fddfbbfad533d9b06e9987d)
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
21e31c2771