local.conf.sample: remove reference to local.conf.extended

JIRA: SB-3113

Signed-off-by: Christopher Larson <kergoth@gmail.com>
local.conf.sample: disable prelink by default

JIRA: SB-2991

Signed-off-by: Christopher Larson <kergoth@gmail.com>
Merge pull request #233 from kergoth/sb-2991

Disable prelink by default