from a range address

trying to make all SbxVariables reference count their parents
is ludiciously hard, so just reference count this one known
crashing case

Change-Id: Ie1fa6624e8184146dd00d766cdbacef674153ef6
Reviewed-on: https://gerrit.libreoffice.org/26272Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>