classes/package: print command output when commands fail

classes/package: print command output when commands fail

When external commands such as debugedit fail, it can be useful to see
their output, so use oe.utils.getstatusoutput() instead of
subprocess.call() to capture this and print it on failure.

(From OE-Core rev: 34179cc78b730ecb8ff3f4feb4beee2d17498ce3)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>