debug/elf: repair GNU version symbols.
debug/elf: repair GNU version symbols.

After the revert of revision 9ea9e7e6e0c8
the related revision 76ff7da868c6 must be reverted too.

Fixes issue 5102.

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/7961044

wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang,firebitsbr/golang-old,firebitsbr/golang-old