util/cutils: Remove unused qemu_get_exec_dir

qemu_get_exec_dir has been unused since commit:
  5bebe03f51 ("util/cutils: Clean up global variable shadowing in get_relocated_path()")

Remove it, and fix up a comment that pointed to it.

Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2 files changed