15.04: incomplete debug symbols package - please disable CONFIG_DEBUG_INFO_SPLIT or package the .dwo files

The kernel option CONFIG_DEBUG_INFO_SPLIT has been enabled in vivid (commit bb5f2d940954fb389f16a0f7ad05b5a53a7e5227).

It moves debuginfo to .dwo files, using gcc -split-dwarf.
The kernel packaging received no updates to include the .dwo files, AFAICT.

This results in gdb/crash not unable to find/read the kernel debug symbols, because the .dwo files are not present.

Possible solutions include:
1) Disable CONFIG_DEBUG_INFO_SPLIT
2) Update the packaging to include .dwo files.

Options #1 (patch attached) tested, and it worked.

Before:
----------

 # grep CONFIG_DEBUG_INFO_SPLIT /boot/config-3.18.0-9-generic
 CONFIG_DEBUG_INFO_SPLIT=y

gdb:

 (gdb) symbol-file /usr/lib/debug/boot/vmlinux-3.18.0-9-generic
 Reading symbols from /usr/lib/debug/boot/vmlinux-3.18.0-9-generic...
 warning: Could not find DWO CU arch/powerpc/kernel/.tmp_prom_init.dwo(0xa3396d7f33b2feee) referenced by CU at offset 0x24c [in module /usr/lib/debug/boot/vmlinux-3.18.0-9-generic]
 <and many other .dwo files>

crash:

 gdb called without error_hook: Dwarf Error: CU at offset 0x24c references unknown DWO with ID 51757104ad7ccc06 [in module /usr/lib/debug/boot/vmlinux-3.18.0-8-generic]
 Dwarf Error: CU at offset 0x24c references unknown DWO with ID 51757104ad7ccc06 [in module /usr/lib/debug/boot/vmlinux-3.18.0-8-generic]

 crash: /usr/lib/debug/boot/vmlinux-3.18.0-8-generic: no debugging data available

After:
--------

 # grep CONFIG_DEBUG_INFO_SPLIT /boot/config-3.18.0-9-generic
 # CONFIG_DEBUG_INFO_SPLIT is not set

gdb:

 (gdb) symbol-file /usr/lib/debug/boot/vmlinux-3.18.0-9-generic
 Reading symbols from /usr/lib/debug/boot/vmlinux-3.18.0-9-generic...done.

crash:

 # crash /usr/lib/debug/boot/vmlinux-3.18.0-9-generic /var/crash/201501221026/dump.201501221026
 <...>
       KERNEL: /usr/lib/debug/boot/vmlinux-3.18.0-9-generic
     DUMPFILE: /var/crash/201501221026/dump.201501221026 [PARTIAL DUMP]
 <...>
 crash>