package.bbclass: replace rpm/debugedit with dwarfsrcfiles

package.bbclass: replace rpm/debugedit with dwarfsrcfiles

Debugedit provided by rpm 4.14 is rewriting binaries in-place, and was
found to produce broken output at least for grub:
http://lists.openembedded.org/pipermail/openembedded-core/2017-November/143989.html

A replacement utility was suggested via private mail:
https://lists.fedorahosted.org/archives/list/elfutils-devel@lists.fedorahosted.org/message/VZP4G5N2ELYZEDAB3QYLXYHDGX4WMCUF/

(From OE-Core rev: f2e6e1d3bfd4c92ef0f5ed4721fd9050c59dafca)

Signed-off-by: Alexander Kanavin <alexander.kanavin@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>